Ladies Night On Chatroulette #69

ByAHair0304B
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By REBECCA OVERTON
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ByAHair0304B
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Consider a hair.
If it gets in your eye, you want it out.
If it lands on your clothes, you want it
off. Each year, balding men spend
millions of dollars in the hope of replenishing the diminishing supply on
their heads.
To a Paint Horse breeder, a hair can
mean the difference between holding
your breath for 11 months to see if a
foal will be born with Overo Lethal
White Syndrome (OLWS), or knowing you made a genetic cross that ensures you won’t get a foal with the
dreaded disease.
Using hair samples from a horse’s
mane or tail, geneticists at the University of California–Davis can determine if a horse is at risk for producing
lethal white foals. The test reveals
whether a horse carries the mutation
associated with lethal white syndrome
by looking at DNA extracted from a
hair follicle.
Offered by the Veterinary Genetics Lab at the UC Davis School of
Veterinary Medicine, the test costs
$50 and can be ordered by completing a form and returning it to
the lab.
The test requires 25–30 samples of
hair, which must be pulled, not cut,
so that the roots are intact. A horse
needs to be tested only once. Results
are confidential and available within
two to three weeks.
The test was developed by Dr.
Danika Bannasch while Bannasch was
conducting post-doctoral research on
canine and equine genetics. The university began offering the test to the
public in 1998.
During the last five years, the genetics lab has conducted 4,000 to
5,000 tests, a number that researchers
there say is surprising.
“That is a relatively small number
of horses tested when you compare it
with the large number of horses registered,” said Dr. Cecilia Penedo, associate director of the Veterinary
A simple DNA test using
mane or tail hair samples can
help Paint Horse breeders avoid
the heartbreak of producing
lethal white foals.
Genetics Lab. Penedo has worked at
UC Davis as a geneticist since 1982.
“The risk of producing a lethal
white comes when people breed two
horses that carry the overo lethal white
gene,” she explained. “By using the
test, horse owners can determine if
white-spotted horses that are predominantly overo carry the mutation responsible for lethal white syndrome.”
It’s a mystery
The curse of Paint Horse breeders,
lethal white syndrome is one of the
most heartbreaking conditions to afflict spotted horses. Also known as
congenital intestinal aganglionosis,
the disease occurs in Paint Horses that
are all, or predominantly all, white.
Although the foal may at first appear to be normal, it usually begins exhibiting signs of colic within 12 hours
of birth because of a non-functioning
colon, similar to Hirschsprung disease
in humans. Because surgery is not successful, OLWS is always fatal, so foals
are often euthanized shortly after
birth.
The affliction occurs more often in
breeds such as Paint and Quarter
Horses that have white in their coats.
It rarely occurs in Thoroughbreds.
The disease is most often associated
with horses that have an overo spotting pattern. Overo includes three primary patterns—frame overo, sabino
and splashed white—that are genetically different.
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Frame overo horses are characterized by white patches centered in the
neck and body that are framed by colored areas. Research indicates that
frame overo horses are most likely to
produce lethal whites.
The mutation associated with
OLWS also has been found in
horses that have the sabino and
splashed white patterns. The sabino
pattern can range from being minimally expressed in a horse that has
one or more white legs and a blaze
to horses that are almost or completely white. Most sabinos that are
largely white are quite roaned and
speckled.
In the splashed white pattern, a
horse’s legs and the bottom parts of its
body are usually white, which makes
the horse look like it has been dipped
in white paint. Its head is often white
and its eyes are frequently blue.
However, seeing is not always believing when it comes to the complex
world of genetics. Although it has
been shown that frame overos can
produce lethal white foals, the disease
can also occur in tobianos and solidcolored Paint and Quarter Horses
that carry the OLWS gene.
For decades, Paint Horse owners
sought a reliable, scientific way to
identify the deadly characteristic.
When none could be found, many accepted the risk of getting a lethal
white foal as the cost of breeding
Paints.
Then, in 1997, three independent
research groups made a significant
discovery. Geneticists at the University of Minnesota, the University of
California and at a hospital in Australia located the DNA mutation and
gene associated with OLWS. The
Minnesota research was funded by a
grant from the American Paint Horse
Association.
By analyzing the DNA sequence
of the gene in affected foals and
their parents, scientists determined
that lethal white foals have two
copies of the gene responsible for
the disease. As in all genetics, the
offspring gets one copy of a gene
from each parent.
Once the gene was located, the
mystery began to unravel.
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APHA PHOTOS
ByAHair0304B
The overo pattern includes three primary patterns that are genetically
different. Frame overo horses (top) are the most likely to produce lethal
white foals. Although the mutation linked with OLWS has been found in
sabino (middle) and splashed white (bottom) horses, the risk of their
producing lethal whites is less.
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How it works
Inherited diseases, such as lethal
white syndrome, are caused by mutations or changes in DNA. In
lethal whites, a receptor gene contains a change in the order of the
basic DNA building blocks, which
results in a mutation that affects the
normal development of the foal’s intestines.
Animals receive one copy of each
gene, which may be dominant or recessive, from their parents. A horse
that has two copies of the lethal white
gene will be a lethal white.
By knowing a horse’s genetic
makeup and avoiding the crossing of
a stallion and mare that both carry the
lethal white gene, it is possible to produce foals that are overo, but not
lethal white.
With a Punnett Square, scientists
can predict the possible gene combinations when crossing two horses. If
one uses the letter “O” to symbolize
the overo lethal white gene and “N”
for horses that do not have that gene,
lethal white foals can be symbolized
as “OO” because they have two copies
of the lethal white gene.
The overo parents of the aforementioned foal would be represented genetically as “NO.” White-spotted or
solid horses that do not have the mutation would be “NN.”
When two overos carrying one copy
of the OLWS gene, or (NO), are bred,
the resulting ratio of offspring as solids,
overos and lethal whites is 1:2:1. This
means that each time two overos who
carry the lethal white gene are crossed,
there is a 25 percent chance of producing a lethal white foal.
This percentage may not be readily
apparent in real life because not all
lethal white foals survive birth. Some
are resorbed by the mare during gestation or they are aborted.
When an overo that carries the
lethal white gene (NO) is bred to a
solid-colored horse that does not have
the OLWS gene (NN), there is a 50
percent chance of producing an overo
and a 50 percent chance of getting a
solid. There is no chance of producing a lethal white foal.
Many people believe they increase
their chance of getting an overo foal
N
O
N
O
N
O
25%
25%
25%
25%
NN
NO
NN
NO
Solid
25%
Overo
25%
Solid
25%
Overo
25%
NO
OO
Overo
Lethal
N
N
NN
NO
Solid
Overo
Many people believe they increase their chances of getting an overo foal if
they breed two overos. However, as the Punnett Square on the left shows,
these breeders have a 25 percent chance of getting a lethal white. If an overo
is bred to a solid-colored horse that does not carry the OLWS gene (square at
right) they have a 50 percent chance of getting an overo—the same as when
breeding two overos—but without the risk of producing a lethal white.
if they breed two overos, said Penedo.
But research reveals this is not the
case.
“If they breed an overo to a solidcolored horse that does not carry the
OLWS gene, their chance of getting
overo offspring is 50 percent, the
same as if they bred two overos,” she
explained. “But they eliminate the 25
percent chance of getting a lethal
white.”
Equine genetics can be very tricky.
You can’t always tell by looking at a
horse if it carries an overo gene. Tobianos, toveros and solid-colored
horses can all produce lethal white
foals if they have the OLWS gene in
their pedigrees.
That’s where the test comes in.
Using a process called allele specific polymerase chain reaction
(ASPCR), the test makes it possible
for scientists to look at the region of
the gene responsible for the white
pattern.
“Almost everyone working with
DNA uses this process because it allows us to look at a very specific, very
short piece of DNA that contains the
mutation,” Penedo said.
Although no other mutations associated with OLWS have been discovered, there is the rare possibility that
two non-overo horses (NN) could
have a lethal white foal if there is a
mutation at a site different from the
one the test detects.
The test is also useful to breeders
who want to identify pedigree sources
of the overo pattern that may be valuable to their breeding programs.
Looks can be deceiving
Just as you cannot tell whether a
horse is at risk for producing lethal
white foals by looking at its coat, a
completely white horse is not always a
lethal white.
Interestingly enough, the white
gene (W) is dominant over all other
coat colors, including gray. This
means that a foal that receives only
one dominant white gene from either
parent will be white. This horse has
white hair, pink skin and dark eyes.
But even though the white gene is
dominant, scientists know that two
dark-colored horses have produced a
white foal. One explanation is that
the white gene may have a high rate
of spontaneous mutation because
foals produced by such crosses have
gone on to breed as if they had a dominant white gene.
UC DAVIS PHOTO
ByAHair0304B
Dr. Cecilia Penedo is associate
director of the Veterinary Genetics
Lab at UC Davis.
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Whites aren’t always lethal
Peg Fultz couldn’t believe her eyes
as her Paint Horse mare, Ambers Romance, began to foal during the
morning of May 4, 2001.
Peg and her husband, Daniel, had
bred the bay tobiano mare to their sorrel overo stallion, Sonnys Zippin It.
The Fultzes, who own Prism Paints
& Quarter Horses in Bagley, Minnesota, have bred and raised horses for
15 years. Originally, the couple
wanted to breed “Sonny” to another
mare who was a frame overo, but they
decided against it after having both
horses tested for Overo Lethal White
Syndrome (OLWS).
“We knew about lethal whites after
being on horse farms and learning
about it from the Paint Horse Journal,”
Peg noted. “After the test revealed both
horses had one copy of the frame overo
gene, we decided not to breed them.
“We felt it was a matter of responsibility because we knew there was a
25 percent chance of their producing
a lethal white foal and we didn’t want
to create that situation.”
Instead, they bred Sonny to Ambers Romance because she is a tobiano, which doesn’t carry the lethal
white gene unless the horse has overo
in its background.
So, when Peg saw a white coat
emerge as “Amber” began to foal, she
felt uneasy.
“I looked at the baby as it was being
born and saw more and more white
coming out,” she said.
After the foal was finally born, Peg
was devastated. It was a solid white
colt with pink skin and blue eyes.
“He didn’t have a dark spot anywhere,” said Peg. “Believe me, I
looked.
“I almost died because I thought
it was a lethal white. It was heartbreaking.
“Daniel wouldn’t even look at the
foal. He just knew we were going to
have to put him down.”
PEG FULTZ PHOTOS
PPQ Spirit Of Romance (left) is an
example of a viable white horse. His
dam, Ambers Romance (right), is a
bay tobiano. His sire, Sonnys Zippin
It (below), is a sorrel overo.
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The couple knew veterinarians advised euthanizing lethal white babies
so that they wouldn’t suffer.
Peg immediately logged on to
www.horsesmidwest.com, an equine
chat line created by horse owner Pat
Bores, for advice and comfort from
on-line friends.
“I wanted to talk with them about
what I thought was a horrible situation,” she recalled.
“Some said to wait and see if the
foal exhibited lethal white symptoms.
They advised me to wait before doing
anything.”
Lethal white foals have non-functioning colons, so they are unable to
pass waste. Because of this, they begin
to show signs of colic within the first
12 hours after they are born.
When Peg finally saw the colt pass
meconium, a newborn’s first excrement, she was elated.
But her joy quickly turned to despair.
“I thought we were out of the
woods,” she said, “but then I found
out we needed for the milk feces to go
through. I didn’t see it from Friday
morning, when the foal was born,
until Sunday night.
“Finally, after the third day, it came.
Boy, was I happy!”
The foal’s registered name is PPQ
Spirit Of Romance, but the Fultzes
call him “Houston.” He remained
healthy, and is a good example of a viable white.
Viable whites are usually a combination of equine white spotting patterns. Scientists believe such horses
are white because they have two white
spotting patterns that overlap.
One of the genes may carry the overo
lethal white characteristic, but the other
gene carries another white pattern.
After further research into the
pedigree of Houston’s sire and dam,
Peg believes he carries the genes for
four patterns—tobiano, frame overo,
sabino and splashed white. His base
color is red, or sorrel, according to
the results of a red-factor test conducted by the Veterinary Genetics
Lab at the University of California–
Davis.
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The Fultzes also had Houston
tested for the lethal white gene,
which revealed he has one copy. So
they bred him to PPQ Zena Skips, a
smoky black Breeding Stock who
does not carry the OLWS gene.
They can hardly wait for Houston’s first baby to be born this spring.
The foal could be sabino, splashed
white, frame overo, tovero or Breeding Stock, says Peg.
“Horses like Houston are sometimes referred to as ‘extreme overos,’
which have more than an 80 percent
chance of throwing color,” she said.
“But most important, he’s got
great bloodlines and conformation.
His sire is a full brother to APHA
Champion Sonny Dee Zippin. He
can do everything from hunter under
saddle to halter to Western pleasure.”
Peg credits her on-line friends for
convincing her to wait to see if Houston was healthy.
“If it weren’t for my horse forum
friends, I don’t know if he would be
here today,” she said.
“Later, I had some very heart-felt,
tearful conversations with people
who said they had put down some
all-white foals who hadn’t shown any
symptoms because their vets told
them they would probably die anyway.”
The Fultzes are big supporters of
OLWS testing because it helps breeders avoid crossing horses that can
produce a lethal white foal.
“Financially, the test saves you a
whole year of breeding,” Peg said.
“I don’t think a mare owner
should breed to any stallion, regardless of what he looks like, unless he
has been tested for OLWS. He could
still have the lethal white gene. You
can’t assume Quarter Horse mares
don’t have it, either.”
The test doesn’t discourage people
from breeding for the popular frame
overo pattern.
“So many people love that pattern,” said Peg. “It’s beautiful.
“You can have frame overos, but still
prevent lethal whites from occurring.
People just have to be informed.”
DARRELL DODDS
ByAHair0304B
Solid white Paint Horses and Thoroughbreds are rare. Arctic White is both.
Bred and raised by Dalene Knight, Arctic White is the only living white
Thoroughbred stallion registered with the Jockey Club.
If two white horses are bred, 50
percent of their foals will be white and
25 percent will be dark. The other 25
percent will be lethal, but these foals,
which are homozygous white (WW),
are usually resorbed before birth.
These two lethal conditions, homozygous white (WW) and overo
lethal white (OO), are produced by
two different genes.
APHA lists white as a color on its
registration certificate. The Appaloosa
Horse Club and Jockey Club also recognize white as a color that may be
registered, but the American Quarter
Horse Association does not.
Solid white horses are rare in Paint
Horses, Appaloosas and Thoroughbreds. In fact, the only living white
Thoroughbred stallion registered with
the Jockey Club is registered as a Paint
Horse, as well.
The horse, Arctic White, was sired
by Airdrie Apache, who is also a double-registered Paint/Thoroughbred
stallion. Arctic White’s dam is Out of
Tropicana Anna (TB).
Arctic White was bred and raised
by Dalene Knight of Painted Desert
Farm in Redmond, Oregon. In 2003,
he was sold to Shadow Mountain Stables in Norco, California, which plans
to use him to breed white Thoroughbred racehorses.
Horses of other colors, such as perlino and cremello, can look white, but
they are also genetically different from
white overos. Perlinos and cremellos
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REBECCA OVERTON
ByAHair0304B
Perlinos may look white, but they are actually bay horses whose color has
been lightened twice by a cream gene. RFF Starbuck, shown here with
owner Milynda Milam, is APHA’s first registered perlino.
are double-diluted, which means they
carry two copies of a color-dilution
gene called the cream gene.
The cream gene in double dose lightens, or dilutes, black and red, the two
basic pigments of equine coat color, to
a very pale cream that sometimes may
appear to be white. It has nothing to do
with the lethal white gene. For example, a perlino is a bay horse whose color
has been lightened by two doses of the
cream gene. A cremello is a red horse
whose color has been lightened by two
doses of the cream gene.
Then there are horses called viable
whites that are often a combination of
two white patterns.
APHA registers viable whites as
Breeding Stocks because the animals
have no other color with which to
contrast the white. This means they
don’t have a qualifying spot that enables them to be eligible for the Regular Registry, explained APHA Registration Manager Cindy Grier.
But some lethal whites have pigment
somewhere on their bodies, she noted.
“They may have a small dark spot on
their nose or under their tails,” she said.
“That pigmented area does not ensure
that a horse is not a lethal white foal.
“However, it’s equally important
to note that just because a horse is
white or 99 percent white doesn’t
mean it’s lethal. Only time or the test
will tell.” f
Want to know more?
If you would like to order the test for Overo Lethal
White Syndrome, or for more information about it, visit
the University of California–Davis Web site at www.
vgl.ucdavis.edu, or call (530) 752-2211.
The following pamphlets, books and Web sites are also
helpful:
• American Paint Horse Association’s Guide to Coat Color
Genetics. To order, call (817) 834-2742, extension 271.
APHA’s Web site also has information about coat color
genetics at www.apha.com/breed/geneticeq.html.
• Equine Color Genetics by Dr. D. Phillip Sponenberg.
Published by Iowa State University Press. To order, call
(800) 862-6657.
• Horse Genetics by Dr. Ann T. Bowling. Published by Oxford University Press. To order, call (800) 445-9714.
• Horse Color Explained by Jeanette Gower. Published
by Trafalgar Square Publishing. To order, call (800)
423-4525.
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• The Cremello and Perlino Educational Association Web
site at www.doubledilute.com.
The following scientific papers on lethal white syndrome
are available at many public libraries:
• Endothelin receptor B polymorphism associated with
Lethal White Foal Syndrome in horses. By E. M.
Santschi, A. K. Purdy, S. J. Valberg et al. Mammalian
Genome 9:306-309 (1998).
• A missense mutation in the endothlin-B receptor gene is
associated with Lethal White Foal Syndrome: an equine
version of Hirschsprung disease. By D. L. Metallinos,
A. T. Bowling and J. Rine. Mammalian Genome 9: 436431 (1998).
• A dinucleotide mutation in the endothelin-B receptor
gene is associated with Lethal White Foal Syndrome
(LWFS); a horse variant of Hirschsprung disease
(HSCR). By G. C. Yang, D. Croaker, A. L. Zhang et al.
Human Molecular Genetics 7(6):1047-1052 (1998).
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GRAY
isn’t a “color.”
Breed associations have
co-opted the term for
registration purposes,
but graying is actually
an aging process that
eliminates a horse’s
normal coat color.
COURTESY CELESTE FENDER
By Tracy Gantz
Horses are not born gray. They“gray
out” over time. For example, HBF
Iron Man was a bay foal. The only
clues to his eventual coat change
were the rims around his eyes.
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When a person’s hair starts to turn
gray, we realize they are getting older.
Yet, when we think of gray in horses,
we often simply see color—he’s sorrel,
bay or gray.
But when it comes to graying,
horses aren’t that different from us.
People are born with blond, brown,
black or red hair, and, at different
rates for each of us, our hair gradually
loses its color and becomes gray, perhaps even white. In humans, gray isn’t
a color, and this is a principle we
should also apply to horses.
“There’s the misconception that
gray is a color, and it isn’t,” said Dr.
Bonnie B. Beaver. “Gray is a white
pattern imposed on a base color.”
A veterinarian and specialist in animal behavior at Texas A&M University, as well as a breeder of Palominos,
Beaver co-authored the book Horse
Color with Dr. D. Phillip Sponenberg,
professor of pathology and genetics at
the Virginia-Maryland Regional College of Veterinary Medicine.
It’s easy to label a horse a particular
color based on what we see. That’s
how breed associations initially began
registering colors, before equine genetic research revealed that a gene separate from body color controls gray.
“Gray is dominant,” said Sponenberg, who has also written the book
Equine Color Genetics. “So gray horses
should have a gray parent.”
Horses are born with a particular
body color, and if they inherit the
dominant gray gene from their sire or
dam, they will eventually lighten to
gray. Some become gray at a very
young age, while others take years to
gray out.
“I don’t know of any way to predict
the speed with which a horse will go
gray,” said Sponenberg. “It does differ
somewhat breed to breed, implying
that genetics plays a role.”
Graying can dramatically change a
horse’s look as it ages. Five-time World
Champion HBF Iron Man, for example, looked much darker when he was
winning at the World Show as a 3year-old in 1999, than he does today.
“HBF Iron Man was bay when he
was foaled,” said Celeste Fender, who
co-owns the stallion with Robin Degrafe and who raised him from a colt.
“He had a little rim of gray around his
eye. His barn name when he was
young was “Rusty” because he was a
rusty color.”
Yet, by the time HBF Iron Man was
winning his first world championship
at age 3, he was a dark gray. Today, the
now-10-year-old stallion is a much
lighter gray, with only the black
points of his original color left on his
legs and the tips of his ears.
Gray in Paints
Because the Paint breed developed
from the amount of white that occurs
on a horse’s body, graying can be a
challenge for Paint breeders and owners. As the gray lightens a horse’s original body coat color, it becomes
harder to distinguish between the
color and the white areas of a horse’s
body. If a horse is going to gray, it’s
important to register the animal early,
especially if it has minimal white.
“When people submit their registrations early in the foal’s life, determining eligibility isn’t difficult,” said
Cindy Grier, manager of APHA’s reg-
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COURTESY CELESTE FENDER
Gray genes
Because the gray gene is dominant,
it is relatively easy to get a gray horse.
While the study of genes is by no
means complete, we do know that
genes occur in pairs, with each parent
giving one of the pair to its offspring.
We can designate the gene for gray as
“G” and the gene for non-gray as “g”
to indicate that gray will dominate
over non-gray. In other words, if a
horse receives a “G” from one parent
and a “g” from the other, it will gray
because the “G” is dominant and the
“g” is recessive.
When a horse receives both a dominant and recessive gene, it is heterozygous for the trait—it has one of
each. If the horse receives two dominant genes (graying would be indicated by “GG”), then it is homozygous dominant, whereas if it receives
COURTESY CELESTE FENDER
istration department. “It’s when they
wait until the horse has grayed that
determining eligibility can be more
difficult. The contrast between a true
white marking and a gray coat color
can sometimes be difficult to differentiate in photographs.”
In most horses, the skin retains the
original body color when the horse
grays, whereas white patches have no
pigment at the skin level. Because of
that, one trick that works to show the
contrast between gray and white is
hosing down the horse with water.
“Often, a trusty garden hose will
help us ‘see’ the horse’s original body
pattern,” Grier said.
Grays make up only 1.6 percent of
the total number of Paints registered,
according to Grier. But she added that
the number should probably be higher
because it doesn’t include horses that
were originally registered as their base
color without the registration being
updated when they grayed.
Paint breeders are more likely to
breed for typical Paint color patterns,
such as tobiano and overo, or performance traits, which may be another
reason for the small amount of gray in
the breed. By contrast, breeds such as
the Lipizzaner and the Percheron are
almost all gray, while gray is also very
common in breeds like the Arabian.
A horse of a different age—not color. As is the case with all horses that go
gray, 10-year-old HBF Iron Man has appeared to develop more white hair each
year of his life. In truth, the stallion’s bay hair has simply lost its color.
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G
g
G
GG
Gg
g
Gg
gg
G
G
g
Gg
Gg
g
Gg
Gg
Above, the box on the left shows that a heterozygous gray (Gg) sire and dam have a 25 percent chance of producing
a homozygous gray (GG) foal, a 50 percent chance of producing a heterozygous gray foal and a 25 percent chance of
producing a non-gray (gg) foal. On the other hand, as the box on the right indicates, having one homozygous gray parent will guarantee a foal that will turn gray, even if the other parent is another color.
and 25 percent non-grays (homozygous recessive for gray). Visually, that
would mean 75 percent gray horses.
Of course, just like a coin flip
would theoretically produce 50 percent heads and 50 percent tails, but
doesn’t, breeders won’t get those exact
percentages either.
Or, as Beaver added with a laugh,
“We all know that if you breed for a
particular color, you won’t get it.”
Plus, a gray stallion’s book won’t consist entirely of gray mares. Likewise, a
gray mare will probably not be bred to
a gray stallion every year. Instead, gray
horses are usually bred to horses of a
variety of colors. All of the non-grays
they are bred to will be homozygous
recessive for gray. When a heterozygous
gray is bred to a homozygous recessive
for gray, the offspring should be half
gray and half non-gray.
Beaver said that she is not aware of
a genetic test to determine whether a
gray horse is homozygous or heterozygous. If a horse produces even
one non-gray, then it is heterozygous
for gray. The opposite is not necessarily true, however, because no matter
how many foals a horse produces,
chance—instead of genetics—could
make them all gray.
HBF Iron Man is a good example
of how a heterozygous gray stallion
APHA FILE PHOTO
two recessive genes (“gg”), then it is
homozygous recessive.
If a horse is a homozygous gray
(GG), all of its offspring will be gray.
If it is homozygous recessive for the
trait (gg), then it will not be gray and
will not be able to pass gray on to its
foals. However, such a horse could get
a gray foal if bred to a horse with a
dominant gray gene (GG or Gg).
Most gray horses are heterozygous
gray (Gg). That means that they can
contribute either a dominant or recessive gene for the trait. Theoretically,
two heterozygous gray horses would
produce 25 percent homozygous
grays, 50 percent heterozygous grays,
Paint racehorse Aze Beduino was sired by the gray Thoroughbred Beduino. Since The Jockey Club began listing gray
and roan as one color, Paint owners have had problems predicting if their half-Thoroughbred foals will turn gray.
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typically reproduces. From his first 75
foals, the stallion has sired 36 grays
from books that include mares of
many colors.
When crossed three times with the
sorrel overo mare Miss Sonny Bonanza,
HBF Iron Man has sired three gray
foals, whereas when crossed four times
with the chestnut overo mare HBF Flirt
N Fancy, he has sired two grays, a bay
and a chestnut. And when bred twice
to the sorrel mare Eagley Jazzed, he has
sired a bay and a chestnut.
HBF Iron Man and the gray mare
Eternally Matched have produced
two grays, while he and the gray mare
Wicks Park have produced one buckskin.
Fender said that though her bloodlines reflect the performance traits she
is looking for, she was hoping HBF
Iron Man would be gray. Likewise,
breeders who take their mares to the
stallion are also hoping that they will
get a gray foal along with the stallion’s
performance ability.
“They consider gray a bonus,”
Fender said.
Determining color
Even though gray isn’t genetically a
color, when it comes to registering
horses, it is considered a color. APHA,
as do most other major breed associations, labels gray a color for registration purposes, and gray trumps all the
others. In other words, if you have a
sorrel, bay or black horse that will
eventually turn gray, it should be registered gray.
It’s still helpful to know the base
color of a gray horse, especially since
base coat color and gray are controlled by two different genes. In fact,
in Equine Color Genetics, Sponenberg
writes that horses get their color from
11 genetically independent processes.
These include genes that cause white
patterns in Paints, as well as genes
that dilute such basic colors as bay
and chestnut/sorrel into colors such
as buckskin, palomino, cremello and
perlino.
Because gray acts on the base coat
as the horse ages, it is sometimes difficult to know the original base coat
color of an adult horse.
“Gray doesn’t tell me anything,”
said Beaver, who in breeding Palominos is very concerned with base coat
color. “If you don’t know a gray horse
when it is young, you may not be able
to know its base color.”
Beaver cites the example of a gray
horse that has black points on his legs,
mane, tail and ears.
“People assume that the horse was
originally black,” she said. “But he
could have been bay, grullo or buckskin. These horses are not going to
breed like a black horse. They are going
to breed what the base coat was.”
Enter the “color” roan to confuse
things even further. Like gray, roan
isn’t genetically a color. However, instead of introducing white hairs as a
horse ages, like gray does, roan sprinkles white hairs among the horse’s
base coat color from birth, and the
amount of white does not change
with age. Also, the roaning pattern
may not be consistent throughout the
horse’s body. It may concentrate in
such places as the hindquarters, girth,
barrel and tail dock. It is also possible
for a horse to be a gray roan.
APHA and the American Quarter
Horse Association distinguish between gray and roan. The two organizations even have different colors of
roan. APHA allows owners to register
blue, red and bay roans. Yet, The
Jockey Club, which registers Thoroughbreds, has combined gray and
roan into one color classification to
reduce the number of corrected registration certificates. The Jockey Club
acknowledges that the two colors differ genetically, but its combination of
the two can introduce confusion
when a Thoroughbred becomes part
of a Paint or Quarter Horse pedigree.
HBF Iron Man received his gray
gene from his dam, the Thoroughbred mare Strawberry Lane. The
Jockey Club had registered her as a
roan, an incorrect designation that
can be discovered by looking at her
pedigree and produce record. Strawberry Lane traces back through her
sire to the gray Thoroughbred champion Native Dancer and through her
“roan” dam to her gray second dam,
Lou-Sepha. Strawberry Lane not only
Melanoma
and
GRAY
horses
Because the skin of gray
horses tends to have more
melanin in it than that of other
horses, gray horses can be more
prone to developing melanomas,
or small tumors on the skin.
Though they are rarely fatal,
melanomas can be unsightly and
can cause chafing, if they interfere with tack.
Melanomas do not usually
occur in younger horses. They
can often be found under the
dock of the tail, around the genital area, near the ears and eyes
and in the jugular area. Most
melanomas do not cause the animal any pain, and they don’t
often metastasize, as melanomas
can do in humans. Thus,
melanomas may not cause a
problem to the horse during its
normal lifespan.
Surgery and laser treatment
can be used to remove
melanomas, but veterinarians do
not always recommend this
course of action. As with any
equine health issue, you should
consult your veterinarian as to
what, if anything, should be
done in each particular case.
8/2/06
11:33 AM
Page 64
produced the obviously gray HBF
Iron Man, but also the 1993 Thoroughbred filly Cranberry, who was
registered as a “gray/roan.”
Registration difficulties
Even though APHA offers many
different categories of color, people
can still have trouble properly identifying their horse at registration time.
Roans may not have enough of the
roaning pattern for easy identification,
while gray will often not show up before a horse needs to be registered.
“People who have raised a lot of
gray horses know what to look for,”
Beaver said. “A foal who will eventually turn gray may have a dustier color
around their face. But if you’re not
used to it, you won’t pick it up.”
APHA’s Grier agreed with Beaver.
She said that an ultimately gray horse
that as a foal looks sorrel or bay, for
example, will often have an unusual
hue compared to a non-gray foal of
the same base color.
Fender noted that while she could
tell that HBF Iron Man would gray as
he got older, the stallion’s first foal,
HBF Drop Your Irons, fooled them.
“Drop Your Irons was a bright
cherry red when he was born,” Fender
said. “He had no gray around his eye
or anywhere.”
Registration photographs can often
help in determining whether a horse
should be registered gray. The APHA
registration department can raise the
question with an owner if a foal’s photos indicate that it may eventually
turn gray.
Parentage also provides a clue because genetically a gray horse must
have at least one gray parent. If it doesn’t, then usually a mistake occurred
when the parent was registered.
“We see obviously graying foals that
do not have a gray parent, but gray is
apparent in the pedigree further
back,” Grier said. “The sire or dam
obviously was registered as its base
color and never updated.”
If that happens, APHA contacts the
owner of the parent whose pedigree
suggests that’s where the gray came
from, requesting current photos and
the original registration certificate.
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AUGUST 2006
Most of the time, the parent is confirmed gray and its information is updated. However, if that cannot be
confirmed or the photos of the parent
show it not to be gray, then APHA
will require parentage verification.
While it may be tempting with a
possibly gray foal to wait on registration, that may not be convenient for
those who want to show a foal early.
Grier also advised registering early so
that a Paint’s white areas show up
their best, noting that it is easy to
amend a registration certificate later.
“All a member needs to do is return
the original certificate, current photographs of the horse and a note or
completed correction form requesting
the change,” Grier said. “Color
changes are done at no charge to
APHA members.”
If a horse’s base coat color is one of
the lighter, diluted colors, such as
palomino or cremello, gray can be especially difficult to determine.
“A cremello, for example, could go
gray,” said Sponenberg, “but would
still end up being a pale, pinkskinned, blue-eyed horse.”
Mapping the gray gene and developing a test for it may eventually solve
these registration problems. Work is
being done to map more of the
equine genome, and it has been reported that a team of researchers in
Sweden is working on the gray gene.
Until then, gray will continue to draw
primary attention through its dramatic “color.”
“A lot of people like gray horses,”
Fender said. “They really stand out in
the ring.” P
GAVIN EHRINGER
060-064-GrayPoupon
Gray Paints, such as the tobiano mare Chiqua Little Lena (pictured with owner
Sandy Kaplan), are growing in popularity because of their unique eye-appeal.
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No, it’s not white. APHA’s latest approved color
is a genetically sound way to make sure
registration records make sense.
By REBECCA OVERTON Reprinted with permission from Paint Horse Journal
t happens every time Milynda
Milam takes RFF Starbuck, her
Paint Horse stallion, to a show.
People literally stop in their
tracks and stare at the 5-year-old
Paint.
With his body glowing like a polished pearl, his shimmering gold
mane and tail, and eyes that resemble clear blue opals, “Buck” looks
like a horse out of a Wagnerian
opera, the equine equivalent of the
classically perfect Germanic form.
After passersby regain their
senses, they want to know what
color Buck is. When Milam tells
them “perlino,” most don’t know
what that means.
One horse show judge, who
thought perlino was a country,
asked where it was located. No,
perlino is not a country. It is the
latest coat color approved by the
American Paint Horse Association
for registration.
APHA added perlino—along
with bay roan—to its existing list
of 15 approved colors in 1999.
“A horse can be registered as
perlino if the color can positively
be identified through photographs,
the horse’s get or produce, or red
factor testing,” said APHA Registrar Cindy Grier.
Buck, who is the first horse to be
registered as perlino with APHA,
has two other “firsts” to his credit.
He is the first Breeding Stock stal72
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PAINT HORSE JOURNAL
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lion to earn a Superior, as well as
APHA Champion honors.
Buck lives at Red Fox Farm, the
55-acre breeding facility in Bryan,
Texas, that Milam owns with her
mother, Dr. Linda Milam. The
rare horse has a white star on his
forehead that can be seen in the
right light.
Perlinos are
pearlescent, or
cream-colored horses,
with gold or pale
reddish-orange points.
Their skin is pink.
Their eyes are blue
and their hair has
color, so perlinos
have pigment.
His genetic makeup can take the
guesswork out of a Paint Horse
breeding program, particularly one
geared to throw buckskins and
palominos. To be sure, Buck is a
horse of a different color.
What’s “hot”
So what exactly is perlino? To
understand it, get ready for a lesson in genetics, that microscopic,
Whoville-sized world of genes and
FEBRUARY 2001
chromosomes that determine,
among other things, how an animal looks.
Color, which distinguishes Paints
from other equine breeds, is an
inherited characteristic. Like the
colors of cars or clothing, at times
certain shades become popular
among horsepeople, so breeders try
to produce animals of those hues.
For example, black-and-white
Paints have been in great demand
in the past few years, and recently
palomino and buckskin have
become “hot.”
“Palomino and buckskin Paint
Horses are popular today, much
as black-and-white Paints were
perceived several years ago,” said
Jim Kelley, APHA Registration
Department manager.
Breeders can spend barnfuls of
time and money trying to get a
colored foal, especially one of a
particular color. If a foal does not
have enough white to be registered in APHA’s Regular Registry,
it can be included in the association’s Breeding Stock Registry if it
meets pedigree requirements.
Recently, Breeding Stock classes
have been added to some APHA
RFF Starbuck, shown here with
owner Milynda Milam, is the first
horse to be registered as a perlino
with the American Paint Horse
Association.
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REBECCA OVERTON
072-078-0201 Perlino
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“Buck’s” ears and mane, which are darker than his body, show his place at
the end of the color continuum. A perlino is a bay horse that has been
diluted, or lightened, twice.
shows to allow those horses to
compete.
Pass the cream
Color has two different components—the phenotype (what a
horse looks like) and genotype
(the genes that determine what
color is expressed).
Perlinos are pearlescent, or
cream-colored horses, with gold
or pale reddish-orange points (the
tail, ears, mane and lower legs).
Their skin is pink. Their eyes are
blue and their hair has color, so
perlinos have pigment.
Some, like Buck, have a dark
gold dorsal stripe.
In appearance, perlino is similar
to cremello, a color approved by
APHA in 1997. Cremellos are
also cream-colored and have blue
eyes, but, unlike perlinos, the
mane, tail, ears and lower legs of
most cremellos are the same color
as their bodies.
Dr. Phillip Sponenberg, Professor
of Pathology and Genetics at the
Virginia-Maryland Regional College
of Veterinary Medicine, refers to
perlino, cremello and smoky cream
horses as “blue-eyed creams.”
Smoky creams are also cream-colored, but they have more pigment in
their points than do perlinos and can
also have more color on their bodies,
Sponenberg explains in his book,
Equine Color Genetics.
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Perlinos, cremellos and smoky
creams are not albinos because
their hair and eyes have pigment.
Interestingly, albinism has never
been reported in horses.
“Creams closely approach being
albinos and result from a similar
genetic mechanism, but they lack
the extremely light coat color and
eye characteristics that are typical
of albinos in other species,” Sponenberg writes.
Base Color
Offspring inherit one gene for a
characteristic from each of their
parents. Dominant genes are
expressed, whether an animal
inherits one gene or two.
Recessive genes can be masked
by dominant genes. Perlino and
cremello are incomplete dominants,
genes whose effects on an animal’s
appearance can be detected phenotypically (by looking at the animal).
Perlino, cremello and smoky
cream are also double-dilution
genes, which means horses of these
colors carry two copies of a color
dilution gene called the cream
gene. This gene dilutes, or lightens,
black and red, the two basic pigments of horse color.
Black, bay and brown are considered black-factor colors in equines.
Sorrel and chestnut are factors of
red. When the basic pigments are
modified by other genes, like the
cream gene, they result in a variety
of colors ranging from black to ivory.
Lightened once—or twice
It can be easier to understand
perlino if one thinks of it as the end
result of a continuum that begins
with a bay horse (a horse with a
One Cream Gene
Two Cream Genes
Sorrel: Starting with a red
Palomino: If the red horse
Cremello: If the red horse
based horse, a sorrel or a
chestnut
has a cream gene from one
parent (1), it’s a palomino
has a cream gene from EACH
parent (2), it’s a cremello
Bay: Starting with a black
based horse with a bay gene
Buckskin: If the bay horse
has a cream gene from one
parent (1), it’s a buckskin
Perlino: If the bay horse has
a cream gene from EACH parent (2), it’s a perlino
Black: Starting with a black
Smoky Black: If the black
Smoky Cream: If the black
horse without a bay gene
horse has a cream gene from
one parent (1), it’s a
smoky black
horse has a cream gene from
EACH parent (2), it’s a
smoky cream
FEBRUARY 2001
COURTESY OF THE CREMELLO AND PERLINO EDUCATIONAL ASSOCIATION
12/13/04
SHIRLEY TRUMBO
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bay gene). If the horse inherits one
cream gene from its sire or dam, it
will be a buckskin. If it inherits two
cream genes—one from each parent—it will be a perlino.
So, a buckskin horse is basically
a bay that has been diluted, or
lightened, once, and a perlino is a
horse that has been doublediluted, or lightened, twice.
“You don’t see a perlino’s black
points because of the dilution, but
its points are normally darker than
its body,” Cindy Grier explained.
That’s why Buck has darker gold
on his lower legs, mane and tail.
Likewise, a red-based horse
(that is, a sorrel or chestnut) that
inherits one cream gene will be a
palomino. If the horse inherits
two cream genes, meaning the
red-based horse is lightened twice,
it is cremello.
If a black horse that does not
carry a bay gene inherits a cream
gene from one of its parents, the
result will be a smoky black. If the
black horse gets a cream gene
from each parent (so it has two
cream genes), the black will be
lightened twice, to a smoky cream.
Keep in mind that there are different shades of colors. How light
or dark the color is depends on
the shades a foal inherits.
For example, a buckskin foal can
be dark buckskin or light. That’s
why the equine world—and the
Paint Horse world in particular—
expresses such a rainbow of colors.
Goodbye to guesswork?
Besides their eye-catching color,
perlino horses can have another
trait that sets them apart from other
equines. If a perlino is homozygous
for the black factor (as Buck is) and
is bred to a bay horse, the offspring
will always be buckskin.
Homozygous means a horse has
a pair of identical alleles at corresponding chromosome sites, or
loci. Alleles are one of two or
more alternative forms of a gene
that occupy the same position on
matching chromosomes. An individual normally has two alleles for
each trait, one from each parent.
So a perlino like Buck, who
tested homozygous for black
(genetically written as EE), can
only give his offspring a black
gene. If he is bred to a bay horse
or a chestnut, his get will always be
buckskin.
Again, how light or dark the buckskin is depends on the color of the
mare. If the mare is chestnut or a
light, clear-coated bay, she will produce a light buckskin foal with good
contrast between its points and
body. A dark bay/brown or black
mare could throw a much darker
buckskin that almost looks grulla.
If a bay horse with a red gene is
bred to a perlino that is not
homozygous black (Ee), the offspring can also be palomino or
cremello. So perlino horses,
depending on their homozygosity
for black, can throw palominos,
cremellos or buckskins.
In the world of genetics, which
can be full of surprises, doublediluted horses, like perlinos and
cremellos, are useful breeding tools.
“Blue-eyed cream horses can be
valuable as breeding animals
because they can produce a
desired color 100 percent of the
time,” Sponenberg explained.
One word of caution: Because a
horse has two genes for color (one
from each parent), bay horses can
have one black gene and one red
gene. Because red is recessive,
you can’t tell from the horse’s
appearance that it has this gene.
A red-factor test, which can
identify whether a horse carries a
red gene, takes some of the guesswork out of breeding. The DNA
test is available from institutions
such as the University of California at Davis.
Accurate records
APHA approved perlino as a
registration color to ensure its
records are accurate. If it hadn’t,
it might have registered horses
with genetic pedigrees that eventually wouldn’t make sense.
“APHA’s registration committee
approved perlino as an accepted
color because of genetics,” Jim Kel-
ley explained. “If a perlino were
registered as palomino, where it
would have been registered previously, ultimately it would have produced horses with black points out
of non-black-point Paint mares,
which is a genetic impossibility.
“Adding perlino to our registry
will help ensure our records are
genetically accurate years from
now.”
To a breed like Paints, in which
color is very important, classifying
colors correctly is vital, believes
Buck’s owner, Milam.
“Although perlinos and cremellos look similar, in reality, calling a
perlino a cremello is the equivalent
of calling a bay horse a sorrel, or a
buckskin horse a palomino,” she
said.
“Of course, you wouldn’t do that.
“APHA has been a leader in
providing members with information, information we can use to
make important decisions about
our Paint Horses. Along with sex
and age, color is one of the main
ways to identify a horse.
“It’s important to get it right.”
Want to know more?
For more information about
horse color genetics and perlinos, the following books and
Web sites are helpful:
• Equine Color Genetics by Dr.
D. Phillip Sponenberg. Published by Iowa State University
Press in 1996. To order, call
(800) 862-6657.
• Horse Genetics by Dr. Ann T.
Bowling. Published by Oxford
University Press in 1996. To
order, call (800) 445-9714.
• Horse Color Explained by
Jeanette Gower. Published by
Trafalgar Square Publishing in
2000. To order, call (800) 4234525.
• The Cremello and Perlino Educational Association Web site
at www.doubledilute.com.
• The University of California at
Davis educational Web site at
www.vgl.ucdavis.edu.
PAINT HORSE JOURNAL
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FEBRUARY 2001
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75
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The story
of “Buck”
RFF Starbuck convinced Milynda Milam to join his team.
Milynda Milam was less than
enthusiastic about buying RFF
Starbuck when her mother, Dr.
Linda Milam, suggested it.
In fact, Milynda had no intention
of buying such a clumsy looking
18-month-old colt.
Milynda and Linda, who own Red
Fox Farm in Bryan, Texas, where
they breed custom color sporthorses, saw “Buck” at a stallion
showcase in Austin, Texas, which
was featuring some of their farm’s
stallions.
“Buck was at one of those rather
ungainly periods some horses go
through,” Milynda explained, “and I
was rather vocal about the fact that
I did not think he was the caliber of
our other stallions.
“We had just purchased a cremello stallion, and I didn’t see any
reason to buy another doubledilute horse, especially one that
was so awkward looking.
“I did not want to buy him.”
But Linda was intrigued by Buck,
who was registered as a Breeding
Stock Paint Horse, because he was
taller and more modern looking—
the type of horse that would fit her
farm’s breeding program.
The Milams use Red Fox Farm,
which they bought in 1994, to produce Thoroughbred-type performance horses with color.
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Plus, Linda thought Buck was a
perlino, not a palomino, as he had
been registered.
After much debate and Milynda’s
continued insistence that they didn’t need a horse like Buck (“to the
extent that I would not give my
mother a check from our horse
checking account to buy him,” said
Milynda), Linda and Milynda’s god-
“We had just
purchased a
cremello stallion,
and I didn’t see
any reason to buy
another doubledilute horse.”
—Milynda Milam
mother, Dr. Dianne Sand, figured
out a way to buy the colt.
“They announced he was being
delivered to the farm,” Milynda
said.
Because Buck’s sire and dam, Mr
Starbucks Beau and Southern Sen,
were registered as Quarter Horses,
their colors were not listed on
Buck’s APHA registration papers.
Milynda quickly ordered an eight-
FEBRUARY 2001
REBECCA OVERTON
072-078-0201 Perlino
generation-color pedigree from a
pedigree service.
“As I saw the pedigree come up
on the fax,” she recalled, “I almost
fainted. The first name I saw on the
top sire list was Impressive. My
heart sank.
“I knew at that point why he had
been for sale—he had to be HYPP
positive.”
HYPP, or hyperkalemic periodic
paralysis, is a genetically transmitted muscular disorder linked to
Impressive, a Quarter Horse halter
sire.
Mr Starbucks Beau was listed as
dun; Southern Sen as grullo.
Although Buck’s breeder, Suzanne Grant of Bend, Oregon,
assured Milynda that Buck’s sire
had tested HYPP negative, Milynda
was still worried, so she ordered an
HYPP test on Buck from the University of California at Davis.
Because she had noticed that
Buck’s parents both carried a black
factor, Milynda also ordered a red
factor test to see if Buck was
homozygous for black.
“If so, he would be especially
useful in a color breeding program
like ours that was designed to produce buckskins,” she said.
“Since we prefer buckskin, homozygous black would be another
bonus because Buck would only
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Page 77
throw variants of the black dilute
gene [buckskin and smoky black.]”
Sure enough, when the results of
the HYPP and red factor tests were
returned, both were negative. Also,
Buck was definitely a perlino.
Milynda and Linda were elated
about both.
Because perlino was not a recognized APHA color at the time,
they changed Buck’s registered
color from palomino to cremello.
“At least it was closer to his real
color,” Milynda said.
“As Buck matured, I had begun
to agree with Mom—he was really
looking nice! Although we had
never planned to show him, as he
began to mature I thought he was
nice enough to compete in APHA
halter classes.
“We had never shown in halter
classes because all we had done
was English. But we had a student
working at the farm who had won
some county championships in halter, so she worked with Buck after
she finished cleaning stalls.
“It was a completely backyard
production.”
When Buck was 3 years old,
Milynda began hauling him to
APHA shows that offered Breeding
Stock classes, setting her sights on
a Register of Merit (ROM) in halter.
If he could just get 10 halter points
to earn an ROM, she reasoned, he
could retire to stud with a show
record.
After they started getting halter
points, however, they didn’t want to
stop. At that point, Milynda learned
no Breeding Stock stallion had ever
earned a Superior.
“I had gone from Buck’s biggest
detractor to one of his team,” she
said.
“Getting the Superior became a
crusade for me. The Breeding
Stock classes were always small,
and sometimes there weren’t
enough entries. We literally earned
the 51 points Buck needed one
point at a time.
“After that, we decided to start
him under saddle and try for an
APHA Championship, which no
Breeding Stock stallion had earned,
NOW AND FOREVER PHOTOGRAPHY/FAYE ZMEK
072-078-0201 Perlino
“Buck,” shown here with Milynda (left) and Katrina Worden, Red Fox Farm’s barn
manager, proved he could win in halter and performance.
either. We put Buck with Jeff Beadles of Cypress, Texas, for training,
and set our sights for the Ark-LaTex Paint-O-Rama.
“Held in Nacogdoches, Texas,
the show has many Breeding Stock
classes and is well-known for a
good turnout of Breeding Stocks. It
was one of the shows we had
mapped out for the next year.”
But, to his owners’ surprise, Buck
earned all the points he needed at
the Ark-La-Tex show.
“There was just no way to know
how well Buck would do at his first
show under saddle,” said Milynda.
“He surpassed all our expectations,
winning under every judge in all four
of his classes.
“He was also high-point Breeding
Stock for the show.”
After he earned his performance
points, several mares with show
records were booked to him for
breeding. In 2000, he bred 17
mares, the majority of which will
produce Paint foals.
So far, Buck has thrown two
buckskin foals—Image Of A Star, a
1999 filly, and RFF Son Of A Buck,
a 2000 colt. Image Of A Star is out
of JG Golden Image (AQHA) and
RFF Son Of A Buck is out of
Sonny’s Dandy (JC).
Buck has come a long way from
being a horse that almost everyone
assumed at first was an albino.
“People at shows would tell us it
was a shame he was an albino
because his conformation sure was
nice!” Milynda recalled.
“We have had a lot of interest in
breeding to him. We had no idea
what the response would be to a
Breeding Stock, especially one that
takes a little time to understand his
color.
“There is that little leap of faith
that people who don’t quite understand the genetics have to take, so
it’s good to be able to show them a
foal or pictures.
“We will be forever grateful to
APHA for giving him a chance.”
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Page 78
Meet the Milams
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Linda and John pored over the
book. In 1970, she bought a mare
named Kitten, who Linda thought
was a perlino.
“When I bought her, she had a
buckskin foal at her side, which I
didn’t buy,” Linda said.
“After I bred her to ‘Okie’ (Ro
Jadallah), who was a chestnut, she
had a buckskin, so I knew she was
a perlino.”
Years later, Linda would buy
another perlino, RFF Starbuck, a
Breeding Stock Paint.
“We wanted to
produce an
English-type
tobiano that had
the major advantage
of being a registered
American
Paint Horse.”
—Linda Milam
The Milams’ Arabian program
ended when Linda married, Milynda
was born, and Linda earned a
degree as a chiropractic doctor.
Still, Linda dreamed of having a
horse program again.
During the late 1970s and ’80s,
she kept a few horses for her and
Milynda. Her daughter earned a
bachelor of arts degree from the
University of Houston and a master’s degree in business administration from Texas A&M University.
In the early 1990s, Milynda
decided she wanted to be involved
in a horse program, so mother and
daughter started their search for
breeding stock. After Thoroughbreds captivated them, they
decided to produce quality Thoroughbreds and half-Thoroughbreds
that would excel in English classes.
In 1992, they bought Cannon
Royal, a son of Kentucky Derby
winner Cannonade. After three of
his foal crops were born, the Mil-
FEBRUARY 2001
REBECCA OVERTON
The seeds for Red Fox Farm’s
breeding program were sown
almost 40 years ago, at the same
time Dr. Linda Milam’s interest in
equine color genetics was planted.
Linda and her daughter, Milynda,
bought the 55-acre horse facility in
Bryan, Texas, in 1994. The farm,
which is home to approximately 60
horses, includes 14 stalls, an
arena, several paddocks and a
breeding lab.
It specializes in color sporthorses of American pedigree that
are registered Paints, Quarter
Horses and Thoroughbreds. Three
of the farm’s Paint stallions—The
Spotlight, Hot Brew and RFF Starbuck—are also registered American
Warmbloods.
The farm produces tall, Thoroughbred-type performance horses,
many with color. Inside a paddock
and surrounded by jostling, loudcolored Paint weanlings and yearlings, one cannot fail to marvel at
some of the youngsters who already
stand almost 16 hands.
Linda’s interest in equine genetics started in the 1960s after she
and her father, John Milam, began
breeding Arabians and half-Arabians at their farm in Louisiana. After
they purchased Ro Jadallah, a Polish/Crabbet Arabian stallion, in
1963, Linda became interested in
adding color to her herd.
She was especially attracted by
palomino and buckskin.
In the mid-1960s, an ad for a
small booklet in the back of Western Horseman caught her father’s
attention. Titled Light Horse Production, the book had a large section on horse color genetics. It was
produced by the Florida Department of Agriculture.
“My father was big on education,”
Linda recalled. “He thought if you
were going to do something, you
better know something about it.
“In the ’60s, there was very little
information about equine color and
genetics. This book was one of the
first to explain it in detail.”
Dr. Linda Milam, shown here with her
daughter, Milynda, became interested
in equine color genetics years ago.
ams were ready to try something
different.
“In 1996, we discovered palomino Thoroughbreds,” Linda said.
“We knew we wanted to keep producing the horses we loved; we just
wanted to do it in color.”
By this time, mother and daughter had moved to Red Fox Farm,
where they began assembling a
collection of colorful Paints and
Thoroughbreds. They are assisted
by Katrina Worden, Red Fox Farm’s
barn manager.
“During the mid-1990s, more
information about genetic testing
for homozygosity of the tobiano
pattern became widely available,”
Linda explained.
“As we learned that a true-breeding tobiano could be produced, we
began to see the possibilities of
crossing such a stallion on our tall,
typey Thoroughbred mares.
“We wanted to produce an English-type tobiano that had the major
advantage of being a registered
American Paint Horse.”
Today, the paddocks at Red Fox
Farm are full of that type of horse. c
Misidentified and misunderstood,
the silver dilution gene has been
virtually unknown in the
Paint world until now.
By IRENE
STAMATELAKYS
horse,” recalled Chiodo. “I thought the color
was stunning. I decided to learn more about
it. So I Googled the term ‘silver dapple.’ ”
Chiodo found the Web site of Meadow
View Farm and Champs Guthrie AQHA, a
brown silver stallion, and came across a page
that had close-up photos of silver characteristics—mottled legs, flaxen-tinted mane and
striped hooves.
“As I looked at the close-up of leg mottling,
a light bulb went off,” said Chiodo. “ ‘That’s
the same type of mottling Bella has!’ She also
has the flaxen mane and striped hooves.”
Living in Des Moines, Iowa, Chiodo owns
two Paint mares—Bella, whose registered
name is Wrangled From Heaven, and Bella’s
dam, Stars Angel Too.
“I had always doubted that Bella was a
dun,” said Chiodo. “As Bella aged, her coat
got darker and darker. She is now the darkest
shade of chocolate I’ve ever seen with no dun
characteristics whatsoever.”
With a chocolate-colored coat and other
silver characteristics, Chiodo wondered if her
Paint was possibly a silver. Did they even exist
in the breed?
“I immediately called APHA and asked
them if they had any silver Paint Horses on
file,” she said. “I was told that they did not.”
Not to be discouraged, Chiodo took the
next step.
“I knew it was a long-shot, but I decided to
test Bella anyway [for the silver dilution gene],”
continued Chiodo. “I got the results in about a
COURTESY MEADOW VIEW FARM
ave you ever seen a silver horse?
Not a shiny gray, but a rare and
intriguing silver dilute? Chances
are, you never have. If you have,
chances are you didn’t know it.
Just ask Paint Horse owner Talia Chiodo,
who first learned about them while surfing
the Internet.
“I was just browsing equine Web sites when
I stumbled upon a photo of a silver dapple
Right: Brown silvers are often mistaken for
liver chestnuts. Notice the lightened mane and
tail and dapples on Champs Guthrie AQHA,
who descends from Bow Champ, one of the
two known lines of silver Quarter Horses.
PAINT HORSE JOURNAL u FEBRUARY 2009
u
107
WWW.KENTFOSTER.US
week. I was floored when I saw them. According to Bella’s results, she was a black silver.
“I was even more shocked after I tested
‘Angel’ [also registered as dun]. Her results
came back as buckskin silver. That means she
carries both the silver dilute gene and the cream
dilute gene—a rare combination indeed!”
Like many Paint owners, Chiodo was completely unfamiliar with the silver dilution gene
and the unique colors it produces by lightening the black pigment in the hair. While silver
colors are rare, they are growing in popularity
and certainly in the future we’ll find—or
breed—more silver Paints.
Right: Some foals
with the silver
dilution gene have
white eyelashes,
which they later
outgrow. This is
a secondary
characteristic, not
absolute proof that
your foal is silver.
Silver characteristics
Before genetic testing for the silver dilution
gene was available, silvers were usually identified by their phenotype or external appearance. Primary characteristics are diluted coat,
mane and tail colors. Secondary characteristics include leg webbing, striped hooves, white
eyelashes on foals and sometimes dappling.
This dilution gene is unique because it modifies only the black pigment in the hair, leaving
the red pigment untouched. As a result, silver
108
u
PAINT HORSE JOURNAL u FEBRUARY 2009
CLARE CARVER
Above: Although
not confirmed by
genetic testing,
BN Pecos Pete
certainly looks like a
black silver. With his
light mocha coat,
dapples, and a
flaxen mane and tail
with dark roots, he
displays classic
silver characteristics.
The 2004 solid
gelding is by Black
Ty Affairs Kid and
out of Magnificant
Nina Blue.
will affect black, bay, brown, buckskin, dun and
grullo horses, without changing sorrel, chestnut, palomino and red dun horses. While those
“red” horses don’t express the gene, they are
capable of passing it to their offspring, often
with surprising results.
There isn’t just one silver color but several
that vary with the horse’s base color. In the
past, these colors were called silver dapple,
silver chocolate and red silver, among other
terms. However, to simplify and clarify the
color names, today many breeders describe
horses using the base color plus silver.
Breeder Julia Lord of North Liberty, Indiana, discovered Saddlebreds with the silver
dilution gene in 2002.
are talking about occur on legs with no white
markings. They seem almost universal among
silver Icelandics and Minis, but pretty rare on
silvers in other breeds.”
Also, since horses with a lot of head white
frequently have white eyelashes, it is impossible to classify a Paint as a silver gene carrier
based solely on this characteristic.
Some silver horses have pronounced
dappling, while others do not.
“The term ‘silver dapple’ can be misleading
because not all horses carrying the gene are
silver in color or have dapples,” said Monique
Matson, who owns Meadow View Farm in
Gaston, Oregon, with her husband, Ken.
Not all silvers display these secondary characteristics, but they are helpful in identifying
carriers when the changes in coat, mane and
tail color are very subtle.
Genetics of silver
Experts say that the silver dilution gene was
possibly present in Icelandic horse populations
more than 1,000 years ago. However, the
exact cause of the silver coat color was discovered only recently.
In October 2006, an international team led
by researchers at Uppsala University in Sweden, in association with BMC Genetics, published its study, “A missense mutation in
PMEL 17 is associated with the silver coat
color in the horse.”
The study revealed that a mutation in the
gene PMEL 17 on horse chromosome 6
causes one amino acid to be substituted for
another and is responsible for a dilution of
the black pigment in the hair. The team
In your mind,
compare Andretti
MVF AQHA with an
ordinary bay and
you’ll see where the
silver dilution gene
comes into play by
diluting the black in
the body, mane, tail
and lower legs.
COURTESY MEADOW VIEW FARM
“Silver on a black base color is the shade
that comes to mind first when hearing the
term ‘silver dapple,’ ” explained Lord. “The
body color is diluted to a chocolate or mocha
brown shade, sometimes light enough to
appear similar to a sooty palomino.”
Black silvers are also mistaken for flaxen
liver chestnuts.
“[In bay silvers], the red pigment on the
body is unaffected, while the black on the legs
is slightly diluted and the black of the mane
and tail is more strongly diluted,” said Lord.
“The horse is not quite bay and not quite
chestnut either. Usually the legs are the main
clue that the horse is not chestnut—they will
be much darker than a chestnut.”
Brown silvers are often difficult to distinguish from blacks and bays, says Lord.
“The Agouti test [as the Agouti gene
controls distribution of black pigment] may
be needed to tell apart black-based from
brown-based silvers,” she explained.
Like bays, brown silvers are often mistaken for
chestnuts. The silver gene can also dilute buckskins, duns and grullos. These colors are rare and
harder to identify visually, making them easily
misclassified. Mane and tail colors are important
clues that the silver dilution gene is at work.
“The gene tends to dilute the mane and tail
much more strongly than the body, often to a
silvery-white color, although this can vary and
may darken with age,” explained Lord.
Manes can range from platinum blond, to
flaxen, to slightly diluted. In some cases, the
mane is described as “self-colored” or the same
diluted color as the body.
Silver expert Lewella Tembreull of Pierz,
Minnesota, breeds Shetland Ponies, where the
color is quite common. She explains that in a
typical silver, “the mane changes in shade from
root to tip, with the core of the mane being
the darkest part. The lower tail is the darkest
part of the tail.”
The lower leg color is also affected, says Lord.
“They tend to have lighter hair on the lower
legs, lightest close to the hooves, and the lower
legs are often dappled, which is highly unusual
in other colors,” she explained.
While it is difficult to identify a silver coat
color in newborn foals, young horses do have
other distinguishing characteristics.
“Foals often have hooves with a very
strong and distinct striping pattern and
white eyelashes,” said Lord. “These traits are
helpful for identifying silver in foals but are
gradually outgrown.
“White markings themselves commonly
cause striped hooves. The hoof stripes that we
TALIA CHIODO
Note how the silver
gene has lightened
the mane, tail and
legs of this buckskin.
Stars Angel Too also
carries the sooty
gene which makes
her coat darker than
most buckskin
silvers.
110
u
confirmed that the silver allele (Z) is dominant and, if present, will almost always produce the silver phenotype.
“Horses that are homozygous (ZZ) for
silver seem to exhibit a more diluted coat
color compared to the heterozygous (Zz)
horses, but this indication needs to be
verified,” wrote the researchers.
The exceptions are the red-based horses.
They do not show any effects of the silver mutation and are hidden carriers, capable of producing offspring with silver coat colors when
crossed with horses carrying the black gene.
Once the silver dilution gene was mapped,
a genetic test was developed and commercialized, giving breeders a definitive tool to
distinguish silvers from other similar colors
and identify red-based carriers.
When silvers are misclassified as reds, they
usually go undetected until they produce a
bay, brown or black foal with a red mate. This
raises a flag with breed registries since two red
horses can only produce a red. Before the
silver test was available, the only other option
was to test for the red factor to show the
“chestnut” was genetically black.
“Very, very few people can tell certain shades
of chestnut from certain shades of silver bay
visually,” said Trembreull. “I have years of experience telling the two apart, and there are individuals that I will not even attempt to classify as
silver visually. There are horses that the only way
to determine if they are a silver bay or a chestnut is by red factor and silver testing.”
Geneticists continue to study the silver dilution gene because of eye abnormalities found in
PAINT HORSE JOURNAL u FEBRUARY 2009
Rocky Mountain Horses, Kentucky Saddle
Horses and Mountain Pleasure Horses. For
years, these problems have been attributed to
Anterior Segment Dysgenesis (ASD), a congenital, inherited but not progressive disease that
can affect horses of any breed or color. ASD was
thought to be linked to the silver gene or color.
However, in a recent studies, the eye defects
found in Rocky Mountain and Kentucky Saddle Horses were not those usually associated
with ASD. Also, researchers are not certain if
the problems are linked to a specific bloodline
or to the silver gene. Other breeds have not
found ASD in their silver horses. Further
research is necessary.
Searching for silver
Like any precious metal, silver is rare.
Where did the silver dilution gene come from?
Are there many silver Paints?
According to the Swedish-led study, silver
coat colors are relatively common in Icelandic
Horses, American Miniature Horses and
Rocky Mountain Horses. They have also been
found in the Morgan Horse, American
Saddlebred and Shetland Pony.
In the Morgan breed, “evidence suggests
Headlight Morgan as the possible source of
the gene,” said Lord.
Why is this 1893 “liver chestnut” stallion
significant?
“If he truly was carrying it, it may be much
more widespread than we think, as he sired
not only many Morgan foals, but was also
used as a sire of Quarter Horses on the
Burnett Ranch,” said Lord.
In 2002, the first silver Quarter Horse was
officially discovered—Bar U Champ Binder,
a 1981 silver stallion. His sire, Bow Champ,
was registered as sorrel, but is probably a silver bay, as he sired at least one bay foal from
a chestnut mare.
“It’s not 100 percent certain which side of
the pedigree Bow Champ got it from,” said
Lord. “Both parents are registered as sorrel.”
A few months later, another silver Quarter
Horse line was identified—Ms Barbarella, a
1993 mare registered as chestnut but with a
silver phenotype. Her pedigree included a
long line of “roans” and “grays”—colors that
could have been silver. That line leads back to
Smoky Wheat.
“He is sired by Waggoner, a bona fide gray,”
said Lord, “so Smoky Wheat and his offspring
could have been gray plus silver. But his dam is
just identified as ‘Mare by Headlight Morgan,’
which takes us full circle to the horse identified
as the likely source of the gene in Morgans.”
Because APHA does not officially recognize
the silver colors, it is impossible to accurately
estimate the number of silver Paints.
According to silver enthusiasts, only the two
registered Paints owned by Chiodo are known
to carry the silver dilution gene, confirmed
through genetic testing.
Stars Angel Too is a 1991 buckskin silver
overo mare, registered as dun.
“Angel is not a typical silver buckskin,” said
Chiodo. “She also carries the sooty gene,
which makes her coat much darker than a
normal buckskin silver. Many buckskin silvers
look almost identical to traditional ‘buttermilk’ buckskins.
“Angel is a unique color. Her base color is a
dark caramel. Her legs are dark, but not black.
They are almost a deep burgundy. Her mane
and tail almost look dark red, but with flaxentinted ends.”
Based on photos, Chiodo believes Angel got
the silver gene from her dam, Silver Star Dust.
“I theorize that Silver Star Dust received the
gene from her sire, Silver Buzz,” explained
Chiodo. “His grand-dam, Painted Doll, looks
like she might be silver by her photo. I haven’t
been able to find any photos to trace the gene
back any further than that.”
Angel passed her silver gene to Wrangled
From Heaven, a 2003 black silver tobiano
mare, registered as dun.
“Silver is notorious for ‘progressing’ over
time,” explained Chiodo. “Bella is a completely different color than she was when she
was a weanling or yearling. “Her mane and tail
have always had dark roots with flaxen-tinted
ends. She has striped hooves and marbling on
her legs. In the summer, she usually develops
a ton of gold dapples.”
A silver lining
Undoubtedly, more Paints carry the silver dilution gene. Silver-colored horses are frequently
misclassified and underestimated because it is
so difficult to identify them visually.
“It can be hard to trace the silver gene because
silver ‘hides’ on red-based horses,” explained
Chiodo. “The silver gene can be passed down
through generations of red-based horses without anyone even realizing it, since it will only
show itself when it is passed to a foal along with
at least one copy of the black gene.”
Most silvers are registered incorrectly as
chestnuts, flaxen liver chestnuts or sooty
palominos.
“Remember, it’s only been a short time that
the test has been available,” said Lord, “and
probably very few owners or breeders know
anything about the color.”
As more breeders learn about the gene and
its effects, they’ll turn to genetic testing for
answers and perhaps find precious metal—
silver Paints—hiding in plain sight in their
pastures. p
“I had always
doubted ‘Bella’ was
a dun,” said owner
Talia Chiodo. Dark
chocolate and
dappled, Wrangled
From Heaven is
actually a black silver
with a flaxen-tipped
mane and tail.
See more photos of silver horses and characteristics at
silverequine.com, an educational site developed by silver
breeder and enthusiast Monique Matson, about the silver
dilution gene and how it dilutes black pigmentation.
TALIA CHIODO
Learn more
By IRENE
STAMATELAKYS
76
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PAINT HORSE JOURNAL
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MONTH 2008
Extremely rare,
the real story
and the role
there’s nothing like a real pearl—dilution. Get
behind pearl—once known as the Barlink Factor—
Paints played in the discovery of this little gem.
are not even close to blue—they are
very much light tan.
“I wasn’t sure what his color was, so
I contacted Carolyn Shepard of the
International Champagne Horse Reg-
istry (ICHR). She told me that there
was a newly discovered gene in the
Barlink Macho Man-bred horses.”
Both the colt’s sire and dam—Awesome Mr Conclusion and TNTs Pride
X
With both a pearl allele and a cream allele, One Awesome Moment could
easily be mistaken for a cremello. That’s not possible, of course, since his sire,
Mighty Awesome, is sorrel.
GRAPHICS N KW
KARI SIPES
And Joy—descend from Barlink
Macho Man. Neither champagne nor
cream, it turns out Mr Unusual carried a double dose of an entirely different dilution gene that lightened his
coat color to a shade few breeders
have ever seen.
Even today, very few people are
familiar with this unusual dilution
gene, commonly called the Barlink Factor but now officially named “pearl,”
and the unique colors the gene can produce. Paints played a leading role in the
discovery of the pearl gene—it turns
out that there are dozens of pearls and
pearl-creams and hundreds of pearl carriers in the breed, waiting to surprise a
lucky breeder with an unexpected gem.
The color of pearl
Both the emergence of pearls in the
American Paint Horse and the story
behind the discovery of the gene are
easier to follow once you understand
how the pearl gene works and the colors it produces.
Pearl is a dilution gene that modifies hair color. We’ll look at three specific cases: the heterozygous pearl, the
homozygous pearl and the heterozygous pearl with cream.
The heterozygous pearl has one
pearl allele. There is no visible dilution of the hair coat.
“Most pearls are in ‘plain clothes,’ ”
said Shepard, who played a pivotal
role in the discovery of pearls. “They
are not so obvious.”
Today, these pearl carriers can be
identified through genetic testing. In
It takes two doses of pearl to
change coat color. A homozygous
pearl is visibly diluted—the coat,
mane and tail are uniformly
lightened to a paler shade.
the past, the only way to confirm their
status was through their progeny.
That being said, several owners of
Paint pearl carriers have reported skin
with lighter mottling rather than uniformly pigmented skin. Heterozygous
pearls in the Spanish breeds have not
shown these characteristics.
“The terminology is not yet set in
stone, of course,” said Shepard. “Even
though pearl is not always visible on the
heterozygous non-creams, I’ve been
calling them red pearl, bay pearl, brown
pearl and black pearl. There are folks
who think since you can’t always see it,
you should just call those horses red,
A palomino pearl, One Awesome
Moment has green eyes.
KARI SIPES
W
hen Janet Spears first laid
eyes on the pale, young colt
nursing under his chestnut
dam, she didn’t know what to think
about his strange color.
“I bought Mr Unusual in 2003,
when he was 2 weeks old, from a couple I used to work for,” said Spears. “I
knew he was a little different from the
get-go—just didn’t know until later
how rare he really is.”
Spears describes her overo stallion
as the color of straw, which just didn’t
make sense at the time, according to
the laws of equine color genetics.
Many people thought he was a pale
palomino that would darken with
age. Others said he was a champagne.
“I tested him to verify that his sire,
Awesome Mr Conclusion, was truly
his sire,” said Spears, who lives in
Lyons, Oregon. “I just wanted to
make sure there wasn’t some kind of
mix-up. I knew that he couldn’t be a
palomino. It wasn’t possible coming
from a sorrel stallion and a chestnut
mare, but being he was such a light
color, I tested for cream just to make
sure and he tested negative.
“His color is very hard to explain,
and even harder to catch on film. In
the summertime his coat is very shiny;
even when dirty, he has an unusual
sheen. His eyes are the same light tan
as his body. Around his eyes, nose,
under his tail and around his genitals,
the skin is pinkish-purple with darker
purple-looking specks, similar to
those of a champagne.”
Mr Unusual could easily be confused with a palomino, says Spears,
but not with a cremello.
“He is very different from a
cremello, as there is quite a lot of color
to him, whereas there is mostly only
pink skin on the cremello,” she said.
“Another big difference between him
and the cremello is the eye color. They
bay, brown or black, and note that they
‘carry pearl.’ Once you know they carry,
I think it’s okay to call them by the
‘base color + pearl’ names.”
Paint stallions Barlink Macho Man
and Mighty Awesome are just two
examples of heterozygous pearls.
It takes two doses of pearl to change
coat color. A homozygous pearl is visibly diluted—the coat, mane and tail
are uniformly lightened to a paler
shade. On a red base (sorrel or chestnut), this color is frequently described
as apricot. On a black base, the color
is similar to a dark amber champagne.
In general, skin color is also lightened.
“One interesting thing about the
double pearls is that they can have
really dark eyes,” said Shepard.
Standard names have not been set,
but Shepard calls these colors by the
base color (red, bay, black or brown)
plus homozygous pearl—for example,
red homozygous pearl.
“It’s also perfectly okay to substitute
‘double’ for ‘homozygous,’ ” Shepard
said. “I actually prefer ‘red double pearl,’
as this flows off the tongue better.”
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Finding pearls
In 2001, Carol and Don Schneider
of Durango, Colorado, submitted a
registration application to the International Champagne Horse Registry
(ICHR) for Barlnk Peachs N Cream,
The term “Barlink Factor” was coined in honor of Barlink Macho Man, a “plain
clothes” pearl. “Macho” was not visibly dilute because he was heterozygous
for the gene.
a 1997 solid mare. Registered with
the American Paint Horse Association
(APHA) as a palomino, the mare
appeared to be champagne. (See
“True Champagne” in the October
2008 Paint Horse Journal.)
Shepard, ICHR president and registrar, remembers the case clearly. The
mare’s sire and dam—Barlnk Tardy
Too and Barlink Snoopy Sue—were
sorrels, and no dilute horses appeared
in the first three generations of her
pedigree.
“ ‘Peachs’ didn't have an obvious
champagne ancestor, her color was
not quite right, and her eyes were so
very dark that I just wondered about
her,” said Shepard. “But I couldn’t
think of what else she could possibly
be [besides champagne] with the
characteristics she had, so I gave her
the tentative registration status.”
Shortly thereafter, Shepard learned
of other unusually colored Paints that
looked much like champagnes without champagne parents—R Smoken
Lark, Woodstock Chocoblanco and
Raleighs Barlink. Studying the pedigrees, Shepard realized that the four
horses shared Barlink Macho Man as
a common ancestor.
Following her discovery, Shepard
wrote the first article, published in
the July 2002 issue of the Champagne
Horse Journal, describing a possible
new dilution gene in Paint Horses that
mimicked champagne, yet was different. In tribute to Barlink Macho Man,
she called it the “Barlink Factor.”
Before the test for the champagne
gene was available, when a dilute
horse tested negative for the cream
gene, it was generally accepted as
proof the horse was champagne.
Barlnk Peachs N Cream, and others
like her, tested negative for cream.
Shepard was certain these horses
weren’t champagne and they weren’t
diluted by cream.
About the same time, an unusual
dilution phenomenon in Iberian
horses caught the attention of those
who study equine color genetics. At
first, it was believed that the champagne gene was at work. But that
possibility was gradually eliminated,
and it was discovered that the dilute
horses were related through a common, non-dilute parent. The ICHR
discussion group came to the
conclusion that perhaps
an entirely new
dilution
gene existed that behaved exactly like
the Barlink Factor found in Paints. In
Iberians, this dilution was commonly
called pearl.
Then in 2003, Shepard came across
Barlink Dun N Gold, an apparently
homozygous Barlink Factor dilute
who went back to Barlink Macho
Man on only one side of the pedigree.
The mare was out of My Tontime
AQHA, the grand-dam of Barlink
Macho Man. This proved to be a crucial discovery because Barlink Dun N
Gold was registered as a palomino,
but was by a sorrel out of a red roan—
in effect two chestnut parents—which
was impossible.
For the next three years, Shepard
and others continued to study the
Barlink family of horses, trying to
understand the intricate workings of
this new dilute gene. One question
kept popping up. Why weren’t the
pseudo-cremello horses, with one
Barlink Factor and one cream gene,
producing foals like themselves?
In April 2006, Shepard came up
with a theory.
“Nicole MacPherson and I had
been watching [on a Web site], foal by
foal, as One Awesome Moment’s
COURTESY KAY SIMMELINK
and dam,” said owner Darla
McConnell-Fox of Sandpoint,
Idaho. “He looked cremello or
champagne, but his parentage didn’t
support that. ‘Gold Rush’ has green
eyes and dark pigmentation or
freckling of the muzzle, eyes and
genitalia. He has dark pinkish skin
Owner Janet Spears describes Mr
Unusual, a homozygous pearl, as the
color of straw, very shiny, with light
tan eyes and speckled skin.
APHA FILE PHOTO
Mr Unusual, Barlnk Peachs N
Cream and Barlnktwentyfourkarat are
all homozygous pearls.
The heterozygous pearl with cream
has both a pearl allele and a cream
allele. The two genes interact to produce pseudo double cream dilutes,
with pale skin and blue, yellow or
green eyes. These foals surprisingly
resemble a cremello or perlino, but
often have a parent that is not visibly
dilute, like a chestnut.
The pearl-cream nomenclature is
pretty standard, and the colors are
called palomino pearl, buckskin
pearl, smoky brown pearl, and
smoky black pearl.
One Awesome Moment is a 2000
palomino pearl overo stallion owned
by Triple C Ranch LLC in Smithfield,
Kentucky.
“He is a lighter palomino coloring,
similar to a cremello,” said trainer and
ranch manager Kari Sipes. “He has
freckling around his nose and eyes,
has a lighter pigmentation of skin and
he has green eyes.”
Another good example of a
palomino pearl is the 1988 overo stallion Barlink Gold Rush.
“I knew his color could not be
explained by the colors of his sire
COURTESY JANET SPEARS
COURTESY CAROL SCHNEIDER
Thinking she might be champagne, Barlnk Peachs N Cream’s owners tried to
register the mare with the International Champagne Horse Registry, and
thereby launched the search for a new dilution gene.
everywhere else, and he’s a very
light body color.”
Buckskin pearls are easily confused
with perlinos, says Shepard.
“Buckskin pearls are born a pale
cream color with darker manes and
tails,” she explained. “At this stage,
they closely resemble amber cream
(champagne) foals. The points tend to
fade as the horse ages, such that they
end up looking like perlinos. However, the skin will freckle a bit darker,
and the eyes will turn a shade of yellow-green, which should distinguish
them from perlinos.”
Stars Sunny Delight and Just A
Honey Rose are two examples of
buckskin pearls.
Smoky black and smoky brown
pearls are extremely rare in Paints.
R Smoken Lark appears to be a
smoky black pearl, that is to say, a
smoky black with one pearl gene.
Shepard says his skin is diluted to
near pink and his hair is a very
unusual shade, somewhat resembling a smoky black cream.
Two doses of the pearl dilution gene visibly diluted the sorrel base coat, mane
and tail on Barlnktwentyfourkarat to an apricot color.
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It’s believed that My Tontime AQHA, grand-dam of Barlink Macho Man,
introduced the pearl dilution gene into the Paint breed.
It then became clear that the
Barlink horses were not the sources of
a new mutation, but simply carried
the genes, reflecting the Spanish ancestry of the Quarter Horse and Paint
breeds. Dilute-color enthusiasts then
rallied for the name to be changed
from “apricot” to “pearl” to better reflect the gene’s origins.
The Simmelink story
Although we know today that this
unusual dilution gene was imported
several centuries ago from Europe, it
might have never caught our attention had it not been for the great stallion Barlink Macho Man.
Bred by Kay and Charles Simmelink of Madras, Oregon, Barlink
Macho Man was a 1982 sorrel overo
The success and popularity of
the “ Barlink” horses would
bring an old and rare dilution
gene back into the limelight.
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stallion by Tuffys Two Spades AQHA
and out of Prize’s Bar Link. “Macho,”
a two-time national champion, earned
266 Open points, 52 grands and 30
reserves in halter competition, and was
a Western pleasure point-earner.
As a sire, he is simply legendary.
Macho’s 393 offspring have earned
13,095 halter and 11,195 performance points, propelling the Simmelinks to the top of APHA’s list of
Lifetime Leading Halter Breeders by
points earned, second based on halter
point earners and fifth on the list of
Lifetime Leading Performance Breeders by points earned. (See “High
Desert Dynasty” in the January 1997
Paint Horse Journal.)
The Simmelinks were uniquely
focused on producing overo halter
horses that could also perform.
Unbeknownst to them, the success
and popularity of the “Barlink” horses
would bring an old and rare dilution
gene back into the limelight.
But the Simmelink story actually
begins with Macho’s grand-dam, My
Tontime AQHA. Purchased as 2year-old in 1965, “Tina” was sired by
Tonto’s Time, by Tonto Bars Gill, and
out of My Leo Nita, by My Leo.
Although My Tontime was registered as a red roan, Kay Simmelink
remembers the mare’s coloring as
truly unique.
“My Tontime had such a golden,
deep-burnished, gold-red color under
her red roan-colored coat. She truly
glittered,” said Kay. “With her copper-gold sheen under her roan hair,
she definitely wasn’t like any other
roans we’ve ever seen.”
It has been said that My Tontime
introduced this dilution gene into
the Paint breed. But where did she
get it? As Kay recalls, Tina’s maternal line had some unusually colored
horses as well.
“My Leo Nita—she wasn’t a dun
[as she is registered],” said Kay, who
recalls the mare being a light shade.
“As I remember the pictures, she had
sort of strange-colored eyes. They
weren’t blue but more the color of her
body. I remember thinking she was a
very odd color.”
Kay has also seen old
photos of My Leo, sire of
My Leo Nita.
“He, too, was not the
dun they registered him
as,” she said. “He was
so light—possibly a
diluted palomino.
You could barely
see the white legs
and face. My
guess—cremello—but of
course they [the American Quarter
Horse Association] didn’t register
them at the time.”
What color were they? Unfortunately, we’ll never know. My Tontime
quietly carried both that secret and
the pearl gene, passing them on to her
daughter Prize’s Bar Link and her
grandson Barlink Macho Man.
Macho’s first foal hit the ground in
1985, but it wasn’t until two years
later that the Simmelinks saw anything unusual.
“When we bred Macho to his
grand-dam, My Tontime, the baby
was a beautiful dark golden color
like the statues they used to give out
for AQHA Grands—just glittered,”
recalled Kay.
That cross in 1987 produced Barlink Dun N Gold. Though she was
registered as a palomino, her photo
shows her to be, in fact, a red
homozygous pearl.
At the time, no one knew what to
call this color. As the Simmelinks continued breeding Macho, they eventually made two discoveries.
“We have found that we can get a
gold-colored foal out of breeding
a Macho to a Macho,” said Kay.
“And we did learn quickly not to
cross Macho on palominos or buckskins because he would dilute it on
occasion and at that time it was
not popular.”
In other words, crossing a pearl carrier with a pearl carrier could produce
a homozygous pearl, and crossing a
pearl carrier with a cream carrier
could produce a pseudo-cremello or a
pearl cream.
Over the years, the Simmelinks
have bred a few homozygous pearls,
including Barlnktwentyfourkarat and
Barlnk Misters Gold, both sired by
Barlnk Macho Man Two and out of
Macho daughters. The foals had
gold coloration with same-colored
manes and tails.
“We had to register these colts as
sorrels, so we just sort of assumed they
were diluted sorrels,” said Kay. “We
knew Macho could certainly dilute a
palomino mare, which at the time
wasn’t very desirable like it is now.
Now it’s the rage.
“At the time, anything lighter [than
a palomino or dun] was not desirable.
Now it’s hot property. Had we known
what a goldmine we had, well, we
could have added a lot more of the
light colors to the breeds. All of these
foals, their sire and dams are doubleregistered APHA and AQHA, so it
impacts both breeds.”
For the Simmelinks, first and foremost on their minds was breeding
quality horses that could halter and
ride. Had they been less successful,
the pearl gene probably would have
slipped by unnoticed. Thanks to
their legendary breeding program,
this rare dilution gene, a legacy of
the Paint’s heritage in the Spanish
breeds, is alive and well today.
COURTESY KAY SIMMELINK
COURTESY KAY SIMMELINK
babies were being born,” she said.
“They were all palomino or chestnut
in his first few crops. I was cleaning a
stall one day, thinking deeply as to
why he wasn’t making any ‘Barlink
cream’ babies like himself.
“I’ve never seen a Barlink cream
make another Barlink cream from a
non-dilute mate. They make regular
cream dilutes [palominos, buckskins
and smoky blacks]. Then it hit me.
Barlink must be on chromosome 21,
just like cream. If you look at the pedigrees, Barlink creams come from one
cream parent and one Barlink parent.
That would be why they don’t give
both genes together. They can’t. When
the chromosome numbers divide in
half to make eggs and sperm, each
gamete has only one copy of chromosome 21. So half of the sperm or eggs
carry cream, and the other half carry
Barlink. That means a Barlink cream
will either give out cream or give out
Barlink. There are no other options.”
Shepard had been in contact with
Cecilia Penedo, PhD, of the Veterinary Genetics Laboratory at the University of California, Davis, who was
studying the Barlink Factor. When
Shepard shared her theory that June,
she learned that Penedo was thinking—and researching—along the
same lines. A few months later, in
October 2006, UC-Davis made the
test for the Barlink Factor available to
the public, and the gene was initially
named “apricot.”
In the days following the test
launch, Shepard was on the road,
getting hair samples from an Iberian dilute horse to submit to UCDavis for testing. Results showed
that the mutation found in Paints
was exactly the same as the one
found in Spanish horse breeds, such
as Andalusians and Lusitanos.
Barlink Mister Gold is part of the legendary Barlink family of horses bred by
Kay and Chuck Simmelink. The “Barlinks” brought the pearl dilution to light.
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String of Pearls
Known homozygous
pearls
Ambitious Blonde
Barlink Dun N Gold
Barlnk Misters Gold
Barlnk Peachs N Cream
Barlnktwentyfourkarat
Mr Unusual
Shesa Bita Awesome
TwoTone Gold
Ultimateawesomemoment
WD Whatcha Lookin At
Wildfire Gem
Woodstock Angel Baby
Woodstock Chocoblanco
Known Cream Pearls
Awesome Sugar Cookie
Barlinked In Gold
Barlink Gold Rush
Barlinkscodycandy
Grace N Elegance
Just a Honey Rose
LittleYella Fella
Looking Ata Dream
Machos Ladys Lass
Mighty Alrighty
Miss Cool Image
Mr Awesome Boy
One Awesome Moment
Oro Blanco Woodstock
Raleighs Barlink
R Smoken Lark
SarcoTartanero (also dun)
Sheza AwesomeTicket
Shezablonde Woodstock
Stars Sunny Delight
Twofeathers Karmalita
An Awesome Image
An AwesomeTicket
Annvers Glory
Awesome Andy
Awesome Mr Conclusion
Barlink Classical Joy
Barlink Macho Joy
Barlink Macho Man
Barlink Penny Wise
Barlinks Fancy
Barlinks Jewel
Barlinks Lasting Doll
Barlink Snoopy Sue
BarlinkTriplecash
Barlnk Islebegrand
Barlnk Macho ManTwo
Barlnk MeriTardi
Barlnk Peaches Rita
Barlnks Conclusive Joy
BarlnkTardyToo
Callin Granny
Exclusively Connected
J C Silver Cash
Jetalita Fools Gold
COURTESY RICHARD MARCELLE
Known Pearl Carriers
Ambitious Blonde, a red homozygous
pearl, shows how the apricot color
can vary from horse to horse.
Manchester
Midnight Cassanova
Mighty Ambitious
Mighty Awesome
Mighty Cool Image
MyTontime (AQHA)
Palmer Mountain
Prize’s Bar Link
Shes Mighty Concluson
Sir Nottingham
Sweet Dream Baby
TC Bita Bonanza
TNTs Pride and Joy
TwoTone Barlink
COURTESY JENNIFER CLINE
Real pearls
Like cream, dun, champagne and
silver, pearl is a dilution gene capable of changing base coat colors into
something completely different. It
has been found in Paints, Quarter
Horses, Andalusians, Lusitanos,
Peruvian Pasos and Gypsy Horses.
There are seven known homozygous
pearls, 27 pearl creams and an estimated 1,000 pearl carriers in the
Paint breed.
“It is absolutely fascinating to see
how widespread this is,” said Shepard.
“I wonder why we didn’t notice it
long before we did.”
Currently, APHA does not recognize pearl as an official coat color.
However, now that genetic testing is
available to identify carriers, Paint
pearl owners have one wish.
“I hope someday soon that APHA
will recognize the pearl color,” said
Janet Spears, who owns Mr Unusual.
“Every foal he produces carries the
pearl gene. Mr Unusual is misregistered as a palomino, a color that he
has no genes to produce. I was told
that he would be registered as a
palomino because he looked the closest to that color.”
Jennifer Cline first discovered pearl when she bred Shesa Bita Awesome, and
is working to gain APHA recognition of the color.
Last fall, Jennifer Cline submitted
a proposal to the APHA Registration
Committee to recognize pearl as a
new, approved coat color. Cline, who
lives in Glendale, Oregon, bred and
owns Shesa Bita Awesome, a red
homozygous pearl.
At first glance, Barlink Gold Rush looks like a cremello,
but he’s actually a pearl-cream or palomino pearl.
Cremellos don’t have his dark green eyes and freckling around the muzzle.
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How many Paints carry the pearl gene?
“Barlink Macho Man has 393 registered APHA foals, of
which half would carry pearl,” she said. “Mighty Awesome
has 672 foals. Awesome Mr Conclusion has 135 foals. Barlnk
Macho Man Two has 53 foals. Barlink Gold Rush has 82
foals. Awesome Andy has 102 foals.”
In theory, half of those foals are pearl carriers. Pearl Paints,
says Shepard, greatly outnumber the estimated 250 champagne Paints.
“Right there, just from offspring of those six stallions,
there would be approximately 718.5 pearl-carrying foals,”
said Shepard. “And each of those pearl carriers has 50 percent pearl foals. So there are more than 1,000 of them out
there in the world.”
COURTESY SAM ELLEDGE
DEBBIE KRUGER
This list was compiled by Carolyn Shepard, president and
registrar of the International Champagne Horse Registry,
based on APHA records, pedigree analysis, progeny records
and owner testimonials.
“The horses on these lists are just the ones I know of,” said
Shepard. “There are, without a doubt, many more that have not
come to my attention. This is, by no means, a complete list.”
Registered as a perlino, Stars Sunny Delight is genetically a buckskin pearl.
“My filly is a very unusual color, the
color of apricot,” wrote Cline in her
proposal. “Without a white mane, she
does not carry the cream gene. She
is, however, registered as
palomino as the APHA
does not yet recognize
pearl as a color.
“It seems odd to
me that my registry would be
so involved in
the evolution
of this particular color, yet
not make it a
choice for those who have these
uniquely colored horses and who
have contributed so much in the
research. Our horses are still incorrectly identified as palominos, when
clearly they are not.”
Although the proposal was denied,
Cline has not given up.
“I am very dedicated to getting this
color recognized,” she said.
In the meantime, as more people
learn about the pearl gene and colors,
more pearl Paints are discovered and
their popularity grows.
“I’ll have to admit, however, that
these gold colts are hot property,” said
Kay Simmelink. “Everyone seems to
want that color.” p
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Is your horse a sabino? Geneticists are
working to answer that complex question.
Find out what they’ve discovered and what
it means for your breeding program.
by IRENE STAMATELAKYS
Homozygous SB1
horses are mostly
white, at least 90
percent depigmented
at birth.
all? And most important of all—was
it worth spending the money?
Curiosity finally got the best of me,
and I pulled 30 mane hairs, sent them
off to a laboratory, crossed my fingers
and determined to find out as much as
possible about the Sabino 1 gene. Here’s
what researchers know about sabinos
and whether the Sabino 1 test should be
a part of your breeding program.
An unexpected find
That the Sabino 1 gene mutation
was discovered at all is amazing. Dr.
Samantha Brooks of the University
of Kentucky was actually researching
the tobiano pattern in 2005 when
some unusual foals caught her attention.
“I was on a site visit with a local
Tennessee Walking Horse breeder
to collect some blood from one of
her tobiano horses,” explained
Brooks. “She had two all-white
foals that year, both healthy and
sound, out of rather plainly marked
mares. Both mares had four socks
and a blaze. Since I was there, I collected blood from both foals and
their relatives.
“Once I got back to my office and
did a little research, it became apparent that the pattern on the mares, and
the white coat of the foals, closely resembled patterns produced by simple
The Sabino 1 test allows breeders to differentiate between a horse that is
homozygous for the Sabino 1 gene and one that is heterozygous for the
dominant white gene.
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APHA/DARRELL DODDS
ike many Paint Horse owners, I
like to play “name that coat pattern.” At the novice level of this
game, you have to correctly sort the
tobianos from the overos. At the intermediate level, toveros are thrown in
to increase the difficulty. At the advanced level, you divide the overos
into frame overos, sabinos and
splashed whites. Get bonus points if
you correctly guess the color, too.
Just when I thought I had mastered
the coat-pattern game, I learned that
a genetic test recently became available to determine whether a horse carried the Sabino 1 gene—the cause of
one of the sabino patterns.
Now, I was pretty sure that my
chestnut overo mare was a sabino, so
my curiosity was piqued. Wouldn’t it
be cool to get her tested and find out
for sure? What is a Sabino 1 horse?
How many sabino patterns are there?
What would the test results tell me?
What if my mare wasn’t a sabino after
APHA/DARRELL DODDS
APHA/DARRELL DODDS
Dr. Brooks and Dr. Bailey defined sabino in the horse as a white spotting pattern characterized by white patches with
irregular borders on the face, lower legs or belly and interspersed white hairs on the midsection.
mutations of the KIT gene, a gene I
was already working on because it was
known to be linked to tobiano.”
In the article that resulted from the
research Brooks and her colleague Dr.
Ernest Bailey conducted, it is explained that the KIT gene is responsible for causing spotting in mice, pigs
and humans, similar to the sabino
phenotype found in horses. In the
mouse, the characteristics for heterozygotes are white markings along
the mid-ventral line often extending
to the extremities, white head spots
and some dilution of the remaining
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body color. Homozygotes are completely white with black eyes.
Brooks and Bailey defined sabino in
the horse as a white spotting pattern
characterized by white patches with
irregular borders on the face, lower
legs or belly and interspersed white
hairs on the midsection. The white
areas lack pigment, both in the hair
and the skin.
They hypothesized that the KIT
gene—which had already been linked
to two spotting patterns in the horse,
roan and tobiano—was also responsible for sabino spotting.
“As it turned out, I included the
samples from the white foals with my
tobiano samples when I sequenced
the KIT gene and ‘eureka’—found a
large piece of the gene missing in the
white foals,” said Brooks. “This missing piece is due to a mutation in the
gene that causes it to be abnormally
processed as it is prepared to be used
to make the final protein.”
That “eureka” moment lead to a research project involving three families
of Tennessee Walking Horses and individuals from 12 other breeds, with a
total of 320 horses tested. Blood sam-
ples, pedigree information and photographs showing coat color patterns
were analyzed. In all three Tennessee
Walking Horse families, the only
spotting pattern present was sabino.
Why were Tennessee Walkers the
focus of the study, when so many
sabino-type Paint Horses are available? The answer is simple.
“The problem with studying spotting patterns in the APHA industry is
that there are many, many horses with
more than one pattern,” said Brooks.
“This really causes problems because it
interferes with our ability to define a
phenotype.
“For a while it was more fashionable
to have a solid-colored Tennessee
Walker, so now the variety of spotting
genes is limited in that population. It is
easier to study one spotting pattern at a
time without worrying about other patterns interfering. So I did not use any
APHA families for the initial inheritance studies in that paper.”
In the study, the Tennessee Walking
Horses were divided into three
groups: those without the sabino
spotting pattern, those with the
sabino pattern and those with mostly
white body color who were the offspring of two sabino parents.
During the course of the project,
another interesting question arose.
Were those white foals possibly homozygous for this sabino gene?
The researchers hypothesized that
homozygosity would result in a phenotype with extensive white coat color, at
least 90 percent depigmented from
birth. If the foals were white at birth,
this would exclude the possibility that
they later turned white due to the gray
gene, which eliminates a horse’s normal
coat color as it ages. (See “Gray isn’t a
‘color’” in the August 2006 issue of the
Paint Horse Journal.)
All the white-colored horses that
participated in the study were tested
for other genes that might imitate or
conceal the effects of a sabino gene,
such as overo lethal white foal syndrome causing frame overo spotting
patterns, cream and tobiano.
DNA sequencing showed that horses
expressing this particular sabino phenotype, both spotted and the more extensive white type, had a mutation of
the KIT gene—exon 17 was missing.
Brooks and Bailey were able to prove a
complete link between this mutation,
which they designated as SB1, and this
coat pattern in the Tennessee Walking
Horse families in the study, which they
named Sabino 1.
Five horses were homozygous for
SB1, and all five were white, a phenotype they called sabino-white. The 68
horses with one copy of SB1 all expressed the Sabino 1 phenotype or were
multi-patterned. Some of the multipatterned horses appeared to be all
white, but they also carried genes for
frame overo and tobiano, which
demonstrates an additive effect of white
spotting patterns.
But also of major importance was
the fact that 13 horses expressing
sabino-type patterns did not have
the mutation. Presumably, other genetic factors can also produce what
we describe as sabino.
Define “sabino”
That last point brings up one of
Brooks’ pet peeves.
“You can’t say ‘the sabino gene,’”
Brooks explained. “It doesn’t work
that way. There are many genes
that cause patterns that are commonly described as sabino, at least
five [patterns] that I have seen. All
of these have fundamentally different genetic causes, potentially different genes, so you really have to
specify. It’s correct to say ‘the
Sabino 1 gene’ (SB1) or ‘the sabino
genes.’”
In the case of Brooks and Bailey’s
study, they defined Sabino 1 horses as
those with three of the four following
characteristics:
• two or more white feet or legs
• a blaze or white patch extending the
length of the face
• jagged margins around white areas
• spots or roaning in the midsection
Beyond Sabino 1, it is difficult to
assign definitive names and descriptions to the other patterns in
this group. Common terms used in
the past include “minimal sabino,”
“maximum sabino,” “sabino white,”
“white sabino,” “roaned sabino,”
“sabino roan” and “Clyde-type
sabino.” From a scientist’s point of
view, these are rather imprecise.
“Many people who contact me are
very caught up in specific characteristics—lip spots, for example, or ‘lightning strikes,’” said Brooks. “I’ve had
many an owner tell me that their
horse must be sabino because it has
this one leg with a sock that is pointy
at the top, and that this is a sabino
characteristic. Well, yes and no. Many
sabinos do have pointy socks, but
there are many different biological explanations for pointy socks, only one
of which is Sabino 1.
“When I look at a pattern, I want
to know what may be discernible
about the genetics,” Brooks explained.
Sabino 1 characteristics
Heterozygous SB1 horses generally exhibit three of the four following
characteristics:
• two or more white feet or legs
• a blaze or white patch extending the length of the face
• jagged margins around white areas
• spots or roaning in the midsection
Homozygous SB1 horses are mostly white, at least 90 percent depigmented at birth.
An in-depth description of the characteristics and range of expression commonly associated with sabino patterns is available on the
APHA’s Web site at apha.com/breed/geneticeq4.html. You can also
download APHA’s “Guide to Coat Color Genetics” at apha.com/
forms/guidebooks.html.
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APHA/DARRELL DODDS
APHA/DARRELL DODDS
Dr. Brooks and Dr. Bailey hypothesized
that the KIT gene—which had already
been linked to two spotting patterns in
the horse, roan and tobiano—was also
responsible for sabino spotting.
“I want to know what population of
horses it exists in and what mode of
inheritance it is transmitted by.
“The draft-type sabino, for example, is present in heavy horses, Shires,
Clydesdales, etc. This population,
until the recent popularity of draftcrosses and spotted drafts, was not intermingled much with the light
horses. And, though it seems to be
dominantly inherited, it does not
produce a white phenotype.”
While there is discussion that some
sabino patterns may be polygenic
(coming from more than one gene),
this is not the case with Sabino 1,
which is caused by a single gene—
SB1. The Sabino 1 has a semi-dominant mode of inheritance. This means
that heterozygotes do not look identical to homozygotes.
Although the presence of the single, dominant allele, in this case SB1,
is clearly visible, it’s effect is not as
strong as when two dominant alleles
are present.
Compare this to the tobiano pattern, which is caused by the action of
How does a mutation in the
KIT gene create the sabino
pattern?
According to Brooks and Bailey’s article, the KIT gene encodes the
growth factor receptors of mast/stem cells. Melanoblasts—early forms
of melanocytes or the specialized cells containing melanin—come from
either side of the neural crest in the embryo. These melanoblast cells migrate away from the neural crest toward the extremities, finally becoming part of the epidermis, the outer layer of skin.
Although several factors control the development of melanoblasts into
mature skin cells that produce melanin, KIT signaling is necessary for
that process to happen normally. The alteration of the KIT gene affects
the way it works. Brooks and Bailey provide evidence that shows that
because the KIT gene is missing a piece—exon 17—it causes the white
spotting pattern they named Sabino 1.
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a single, dominant gene. It is impossible to tell with absolute certainty if
a tobiano is heterozygous or homozygous just by looking. In the
case of a Sabino 1 horse, the homozygous horse is clearly different
from the heterozygous horse. The
first is completely white or nearly all
white. The second always expresses
the Sabino 1, but is easily distinguishable from the first.
Even though we classify the Sabino
1 horse as an “overo” pattern, the SB1
gene is not associated with overo
lethal white syndrome. In homozygotes, Sabino 1 produces a perfectly
viable white, or nearly all-white,
horse. Of course, if a horse carried
genes for SB1 and OLWS, it could
potentially produce a lethal white
foal.
A widespread phenomenon?
At this point, no one knows how
prevalent the Sabino 1 gene mutation
is in a specific breed or in the general
horse population.
Brooks and Bailey’s study included
320 individuals from 13 different
breeds. Tennessee Walking Horses
made up the majority of subjects,
with 110 tested. Among those, 67
were not carriers, 39 were heterozygous and had one copy of the SB1
gene, and four were homozygous with
two copies of the gene.
Of the 27 Paint Horses included in
the study, 23 were not carriers, four
were heterozygous and none were homozygous for the SB1 gene. Brooks
states that this doesn’t necessarily
mean that there are no homozygous
Sabino 1 Paints. The researchers simply were not looking for them.
Interestingly enough, the SB1
gene mutation turned up in quite a
few of the American Miniature
Horses in the sample. Of the 29
miniatures tested, 18 were not carriers and 11 were heterozygous.
Animal Genetics, Inc., located in
Tallahassee, Florida, has been offering
the Sabino 1 test for a little over a
year, so the number of horses tested
thus far—276—is still somewhat
small. While this sample is not broad
or random enough to extrapolate the
results to the general horse population, the results are nonetheless interesting.
The breed with the highest number
of horses tested, the American Miniature Horse, had a significant number of
individuals carrying the gene mutation.
More than one-third of the 88 tested—
33—were heterozygous for SB1, and
three more were homozygous.
Five out of the 51 Gypsy Vanner
Horses, the second most prevalent
breed tested, were heterozygous. Results were similar for Paint Horses,
with five out of 42 individuals carrying one copy of the SB1 gene.
While none of the Thoroughbreds
were carriers, one of the 10 Quarter
Horses tested turned up homozygous
for the SB1 mutation, meaning that
this individual could pass the gene on
to all of its offspring.
Although Tennessee Walking Horses
were the focus of the Brooks and Bailey
study, thus far Animal Genetics, Inc.
has only tested four. All were found to
be heterozygous for SB1.
From a statistical standpoint, we
cannot make any generalizations
from the information provided by
Animal Genetics, Inc. However,
based on these findings, it is safe to
say that some Paints and Quarters
carry the Sabino 1 mutation. But
again, this particular mutation does
not explain all sabino phenotypes
(see chart at right).
What are the chances?
Here are the possibilities of producing Sabino 1 offspring when mating two horses.
nn
100 percent nn
nn
nSB1
SB1SB1
50 percent nn
100 percent nSB1
50 percent nSB1
50 percent nn
nSB1
50 percent nSB1
25 percent nn
50 percent nSB1
50 percent nSB1
50 percent SB1SB1
25 percent SB1SB1
SB1SB1
100 percent nSB1
50 percent nSB1
100 percent SB1SB1
50 percent SB1SB1
Source: Animal Genetics, Inc.
nn—Sabino 1 gene mutation not present. nSB1—Both normal and Sabino 1 alleles detected. Horse is heterozygous for Sabino 1 and carries one copy of the Sabino
1 gene mutation. SB1SB1—Horse is homozygous (two copies) for the Sabino 1
gene mutation.
Horse Breed/SB1 Result
Paint Horse
Quarter Horse
Jockey Club/Thoroughbred
nn
nSB1
SB1SB1
Total
37
5
0
42
9
0
1
10
16
0
0
16
American Warmblood
1
0
0
1
Andalusian
3
0
0
3
Arabian
3
0
0
3
Arabian/Dutch Warmblood
1
0
0
1
Drum Horse
1
0
0
1
Falabella Miniature Horse
0
1
0
1
Gypsy Cob
37
0
1
38
Gypsy Vanner Horse
46
5
0
51
Miniature Horse
52
33
3
88
Missouri Fox Trotter
1
1
0
2
Morgan Horse
1
0
0
1
Oldenburg
1
0
0
1
Pinto
3
0
0
3
Rheinland
1
0
0
1
Rocky Mountain
1
0
0
1
Shetland Pony
1
1
0
2
Spanish Mustang
0
1
0
1
Tennessee Walking Horse
0
4
0
4
Warmblood
1
0
0
1
Welsh Pony
4
0
0
4
220
51
5
276
Totals
Source: Animal Genetics, Inc.
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COURTESY DR. SAMANTHA BROOKS
This photo of a Sabino 1 mare and her homozygous foal illustrates Dr. Brooks’ and Dr. Bailey’s research, which proved
a complete link between a mutation of the KIT gene (SB1) and specific coat patterns, which they named Sabino 1.
Implications for breeders
Do you need to test your horse for
Sabino 1? Ultimately, only you can
answer that question. While the test
identifies the gene that only produces
one of the sabino phenotypes, there
are still plenty of valid reasons to have
it done.
Once you get beyond the general
categories of tobianos and overos, de-
termining a pattern based strictly on
photographs has its limitations, especially in horses expressing multiple
patterns. The Sabino 1 pattern can
mimic others, and it is sometimes difficult to differentiate between a sabino
and a frame overo. Brooks also found
that in Tennessee Walking Horses,
many carriers for SB1 were misclassified as roans, which created some con-
Further reading
Brooks S.A. and Bailey E. Exon skipping in the KIT gene causes a
Sabino spotting pattern in horses. Mammalian Genome 16:893-902,
2005.
Brooks S.A., Terry R.B., Bailey E. A PCR-RFLP for KIT associated
with tobiano spotting pattern in horses. Animal Genetics 33(4):301-303.
2002.
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fusion when they later produced
white foals.
“The test can certainly be used to
identify SB1 carriers in multi-patterned individuals where there’s not
enough color left to identify the pattern,” said Brooks. “For example, say
a breeder went out and bought this
great white stallion thinking he was a
medicine hat and expecting to cross
him with solid mares and get tobianos, toveros and frame overos. But
lo and behold, he gets a bunch of foals
with four socks and a blaze. The test
could have identified the stallion as a
Sabino 1 homozygote and not a medicine hat.”
Brooks offers another example.
“You could also use it to identify
minimal white SB1 carriers that
would produce more color when
bred to spotted stallions than your
average solid horse. Say you have an
SB1 heterozygous mare who has four
socks and a blaze, but so little body
white that she’s considered solid.
Half of her foals, when bred to a tobiano homozygote, will have a more
lively tovero (tobiano/sabino) pattern, while half will have only a tobiano pattern. A true solid individual with no spotting genes could not
contribute to the spotting and would
produce only tobianos when bred to
the same stallion.”
The test also allows breeders to
differentiate between a horse that is
homozygous for the Sabino 1 gene
and one that is heterozygous for the
dominant white gene. While the
first, when crossed with a solid
horse, would produce a Sabino 1
phenotype foal 50 percent of the
time, the second would produce an
all-white foal 50 percent of the time.
For the Paint breeder, there’s a world
of difference.
Knowing that your horse is an
SB1 carrier can also reduce some of
the element of surprise come foaling
time. By crossing two SB1 carriers,
you have the possibility of producing a completely white foal that
could easily be mistaken for one afflicted with lethal white syndrome.
The homozygous Sabino 1 horse,
however, is viable and a valuable addition to a breeding program aimed
at producing spotted patterns. By
running tests for both SB1 and
OLWS, a breeder can avoid producing a foal with lethal white syndrome and explain the genetic origin of white offspring.
However, it’s important to keep in
mind that the Sabino 1 test has its
limitations.
“Many people assume that because
their horse has four socks and a blaze it
must be sabino and get upset when
their horse tests negative,” said Brooks.
“Testing negative for SB1 doesn’t necessarily mean that your horse isn’t
‘sabino,’ but some people have a hard
time with that.”
Testing for the Sabino 1 gene
Several laboratories offer testing for the Sabino 1 gene using hair samples from a horse’s mane or tail with the roots attached. The cost ranges
from $25 to $45 per test.
Animal Genetics, Inc.
www.animalgenetics.us
University of California-Davis,
Veterinary Genetics Laboratory
www.vgl.ucdavis.edu/service/horse/
University of Kentucky,
Equine Parentage Testing and Research Lab
www.ca.uky.edu/gluck/EPTRL.asp
In mice, some mutations in the
KIT gene that causes sabino-like
phenotypes result in anemia, mast
cell deficiency, sterility and deafness.
However, it is unknown whether
sabino and sabino-white horses suffer from any kind of health defect.
The owners of the horses sampled in
Brooks and Bailey’s research project
did not report any symptoms of anemia, deafness or sterility.
While she can’t release any specific
details, Brooks is currently investigating what effects SB1 may have on
the immune system and the inflammatory process. This is where Paint
Horse owners can play a role.
“I am in need of horses, and their
relatives, who have tested homozygous for SB1,” Brooks said. “Participation would only require a blood
sample and a short questionnaire. It
does not appear that there are any
severe health deficits in SB1 horses.
In fact, if some of my hypotheses
prove true, they may be protected
from certain inflammatory conditions.”
If you own a horse that has tested homozygous for SB1 and are interested in
participating in the study, contact
Brooks via e-mail at samantha.brooks@
uky.edu or call (859) 257-4757, extension 81174.
Getting results
As for my chestnut overo mare,
test results showed she does not
have the Sabino 1 gene. Once I
overcame my initial disappointment, I reminded myself that it
doesn’t necessarily mean she isn’t a
sabino or that I just lost a round of
“name that coat pattern.” What I
learned during this experience more
than justifies the cost of the test.
My curiosity is satisfied.
Clearly, a great deal remains unknown about the group of patterns
we commonly place under the umbrella term of “sabino.”
“I hope it will be possible one day
to differentiate between all the
sabino patterns by genetic testing
and then name them accordingly,”
said Brooks.
Until then, the discovery of the
Sabino 1 gene and the resulting test
is one more tool that you can use to
understand and more accurately
predict your percentage of spotted
foals. p
“Testing negative for SB1 doesn’t mean
Ongoing research
According to Brooks, some additional work is planned to further
study what—if any—health effects
may be associated with SB1.
that your horse isn’t ‘sabino’.”
—Dr. Samantha Brooks
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DARRELL DODDS
DODDS
DARRELL
Cowboy color: Roan is a
color traditionally favored
by cowboys. Here, Martin
Black rides a red roan at
a production sale in New
Mexico.
Article by REBECCA OVERTON
ou might call The Presidents Hat a genetic impossibility. At least that’s what
the gelding was when the
American Paint Horse Association
registered him in 1998.
Sired by the famous Paint stallion Sacred Indian and out of Continetta (AQHA), The Presidents
Hat was registered as a red roan
tobiano.
But he couldn’t be a red roan.
Genetically, it couldn’t happen.
Although Continetta is a red
roan, Sacred Indian is a bay tovero.
Not just any bay tovero, however.
Sacred Indian is homozygous for
the black and tobiano genes.
“Because he’s homozygous for
black, he can’t produce anything
that doesn’t have black points,”
explained Karen Banister of White
Harvest Farms in Brighton, Colorado. Banister’s daughter, Elizabeth, owns Sacred Indian, and her
niece, Ashleigh Dechant, owns The
Presidents Hat.
“If you breed him to a red roan
mare, his get will always be bay
roans.”
This is because the bay gene is
dominant to the red gene.
Sacred Consuela, a full sister to
The Presidents Hat, is also registered as a red roan, but, like her
brother, she is a bay roan, as well.
APHA listed both horses as red
roans because at the time they
were registered the association did
not recognize bay roan as an
approved color. The horses more
closely resembled red roan than
blue roan, the other roan color on
APHA’s list of approved hues, and
so were given that designation.
Roan, a horse coat color traditionally favored by cowboys, is distinctive, but it can be misleading.
Just because a horse has white hair
mixed in with a base coat of
another color doesn’t automatically make it a roan.
In 1999, APHA added bay roan
to its list in an attempt to identify
coat color as accurately as possible.
“We want to be as genetically
correct as we can,” APHA Registrar Cindy Grier said.
“Sometimes it’s not possible to
go back and correct the old
records, so we’re trying to make
sure the ones we do now are as
complete and correct as possible.
In a case like The Presidents Hat,
we’ll do corrections to our certificates at no charge.”
By October 30, 2001, out of
639,923 horses in APHA’s Regular
Registry, 17,079 were red roans,
3,786 were blue roans and 479
were bay roans.
“There are probably a lot of bay
roans in those red roan numbers,”
said Grier.
APHA verifies a horse’s parentage by looking at photographs of
its sire and dam to see their color.
“We also use get and produce
records to see if a horse has produced any other roan foals out of
a nonroan parent,” Grier noted.
Sometimes it can take a bit of
detective work to determine if a
horse is really a roan.
Name game
In the world of equine genetics,
experts readily acknowledge the
roan pattern is one of the most
eye-catching—and confusing.
One of the reasons identifying
roan can be so challenging is
because the term is used in two
different ways to describe coat
color, explained Dr. Phillip Sponenberg, professor of pathology
and genetics at the Virginia-Maryland Regional College of Veterinary Medicine.
“Roan is a general term used for
the intermixture of white hairs
and colored hairs in all animals,”
Sponenberg writes in his book
Equine Color Genetics.
“In that general sense, all of the
patterns on horses that arise from
such an intermixture could be
called roan. . . .
“It is important to note, though,
that roan also refers to a very specific pattern of white hairs in
horses. As a result, the use of roan
in its general sense can be very
misleading.”
White hair mixed with colored
hair can give a horse’s coat a silvery effect. The roan pattern is
identified by the background color
of a horse’s coat.
Thus, roans come in a rainbow
of hues, such as strawberry,
palomino and purple, the latter
resulting when roan is combined
with mahogany bay, brown and
seal brown.
APHA registers horses as red,
blue or bay roans because chestnut (red), black (blue) and bay are
the basic equine coat colors.
Other equine associations, such as
the American Quarter Horse
Association (AQHA), register
horses as blue or red roan, lumping bay roans in with red as
APHA did before 1999.
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“It’s fairly common to call a bay
roan a red roan,” Sponenberg
noted.
AQHA sometimes runs into
the same registration dilemma
that APHA encounters.
“Because of the different types
of roans, we occasionally find a
horse that throws a roan that,
genetically, it shouldn’t,” said
Gary Griffith, AQHA Executive
Director of Registration.
“Then we get pictures and do
parentage verification.”
APHA added bay roan to distinguish between roans that have
base coats that are bay and those
that have sorrel or chestnut. The
association defines bay roan as a
mixture of white hair on a base
coat of red to reddish brown.
Bay roans usually have black
lower legs, and a black mane and
tail.
The association defines red
roan as a more or less uniform
mixture of white hair and red hair
on a large portion of a horse’s
body. However, its head and
lower legs are usually darker, and
the mane and tail may be red,
flaxen or white.
Blue roan is defined as a uniform
mixture of white hair and black
hair on a large part of a horse’s
body. The animal may have a few
red hairs as well. The color is usually darker on the horse’s head and
lower legs.
In the classic or true roan pattern, the head, mane, lower legs
and tail are always darker.
“The true classic roans with dark
heads and dark feet are pretty rare
in the Paint Horse breed,” Sponenberg said.
Roaning patterns, such as rabicano, add another ingredient to the
mix. Typically, this pattern, which
is also known as ticking, is uneven
and is expressed more heavily on a
horse’s flanks and barrel than on its
forehand.
Rabicano is usually limited to a
few white hairs on the base of a
horse’s tail and on its flank. It is
also known as skunk tail or coon
tail.
In another roaning pattern called
frosty, the mixture of white is more
uneven than in the classic roan.
Frosty horses tend to have roan
areas mainly over bony prominences, such as the hip, over the
shoulder and down the spine. The
mane and tail tend to be roan, and
the head can have roan areas, too.
Still another pattern, sabino, can
include extensive roaning, which
causes some people to confuse a
sabino horse with a roan.
“Extremely roan sabinos can be
confused with classic roan horses,”
said Sponenberg, “but white on the
legs and faces, as well as roan areas
on the head, will give these horses
away as sabinos.
“Roan areas on sabinos are also
less even and uniform than they
are on classic roans, and the areas
are likely to be patched or flecked.”
So what is it?
Roan horses are standouts, to be
sure. In fact, that’s why Kate Mordaunt bought a blue roan stallion
in 2000.
When Mordaunt, of Cedar
Rapids, Iowa, saw Mr Good And
Plenty, it was love at first sight.
“I bought him because of his
color,” she said. “I had never seen
that color of horse before.”
Sired by Zippos Mr Good Bar
(AQHA), Mr Good And Plenty is
out of Jets Classy Doll.
The 6-year-old stallion holds
World and Congress Championships in Western pleasure. He has
sired some red roan babies, and
Mordaunt is waiting to see what
this year’s foal crop will bring.
Standing at Double L Paint
Horses in Cedar Rapids, Mr Good
And Plenty has attracted many
clients.
“We have a waiting list for blue
roan overos,” said Lori Hanson,
who, with her husband, Lyle, owns
the Double L.
“Show people like them because
the color is different. They seem to
want something that stands out on
the rail.”
DARRELLL DODDS
(Continued on page 110)
So sabino: Ropers Reflection is a red
roan sabino. His white legs and face
are clearly sabino traits.
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DARRELL DODDS
Back to the beginning
True roan: This blue roan breeding stock Paint is a classic roan because it has a dark head, mane, lower legs and tail.
According to conventional wisdom, roans are durable and work
well under tough conditions.
“Cowboys used to think roans
were lucky,” Paint Horse breeder
and trainer Karen Banister said.
Cowboys appreciated many
roans’ flint-hard hooves and the
horses’ ability to withstand the rigors of ranch work.
“Roans are popular, but difficult
to get,” Banister said.
Many roans hark back to Roan
Hancock, AQHA Number 456,
who was a 1935 red roan stallion.
Sired by Joe Hancock, a brown
Quarter Horse, Roan Hancock
was out of an unregistered horse
named Burnett Riding Mare.
More recently, Peptoboonsmal
(AQHA), a 1992 red roan stallion,
and his 1972 blue roan dam,
Royal Blue Boon (AQHA), have
made a name for themselves as
producers of outstanding cutting
horses. Both are owned by Elaine
Hall of Weatherford, Texas.
Peptoboonsmal was sired by
Peppy San Badger (AQHA), the
famous King Ranch cutting horse.
Peppy San Badger’s numerous
honors include winning the 1977
National Cutting Horse Association (NCHA) Futurity and the
1978 NCHA Derby.
The sorrel cutter set a record as
the first derby champion to be
sired by another derby champion,
Mr San Peppy.
Peptoboonsmal’s titles include
1995 NCHA Futurity Champion,
1996 NCHA Derby finalist and
finalist at the 1996 NCHA Super
Stakes.
Royal Blue Boon threw Bet Yer
Blue Boons, a 1990 red roan mare
who won the 2000 NCHA Open
Championship. Owned by Oxbow
Ranch of Weatherford, Texas, Bet
Yer Blue Boons was sired by
Freckles Playboy (AQHA).
Another red roan Quarter Horse,
Zippos Mr Good Bar, has sired
many roan Paints. Out of the 1984
stallion’s 28 get in the APHA Registry, 14 are registered as red roans
and one is listed as a blue roan.
Zippos Mr Good Bar, who was
inducted into the National Snaffle
Bit Association Hall of Fame in
2000, has sired multiple World
and Congress champions. He
earned a Superior in Western
Pleasure and is on the AQHA
leading sires list.
Owned by John and Sondra
Narmont of Auburn, Illinois, Zippos Mr Good Bar was sired by the
great sorrel Western pleasure
horse Zippo Pine Bar (AQHA),
and is out of Tamara Wess
(AQHA), a red roan mare.
PAINT HORSE JOURNAL
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109
Genetics lesson
allele (RnRn) is dominant, most
roan horses produce roan offspring 50 percent of the time.
Roan is believed to be linked to
other genes that determine coat
color, which makes establishing
the inheritance of the gene more
complicated because the genes
are usually passed along as a
group.
The roan gene is closely associated with the E gene, which
determines a red or black base
coat, and the tobiano (TO) gene.
Therefore, roans have a high per-
PATTI CAMPBELL
BEN IVERSON
So, what makes a horse a roan
genetically, or, as the experts say,
phenotypically? A roan horse must
have one roan allele, which is written as RnRn.
An allele is one of two or more
forms of a gene that occupies the
same position on matching chromosomes. Chromosomes carry the
genes that determine an animal’s
hereditary traits.
Normally, an individual has two
alleles for each trait, one from
each parent. Because the roan
Red or bay? Irresistable Kid (top), a red roan overo, displays the silvery effect
roaning can have. The Presidents Hat (above), a bay roan tobiano, was registered as a red roan before bay roan was approved by APHA.
110
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PAINT HORSE JOURNAL
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JANUARY 2002
centage of offspring that are the
same color as the roan parent.
For example, when red roans,
which have a sorrel base coat, are
bred to sorrels, the offspring are
50 percent sorrels and 50 percent
red roans. A blue roan, whose
roan gene is linked to its dominant E (black) gene, is likely to
produce a high percentage of
black and bay roans.
If a horse’s roan gene is linked
to the recessive e (sorrel) gene of
a heterozygous (Ee) individual,
the horse should produce only
red roans when bred to sorrel
mates.
Because roan is dominant, theoretically it should never skip a
generation. However, sometimes
that rule doesn’t seem to apply.
“In most cases, a close inspection of the nonroan generation
reveals that the offspring are minimally roaned,” explained Sponenberg.
“This complicates the picture
somewhat, because if you have a
really dark roan horse in which
the roan is not prominently
expressed, sometimes you have
nonroan horses that have a few
white hairs that look the same as
the roan horse.”
Homozygous roans, or horses
that carry two RnRn alleles, are
rare, but more are being discovered. Although it was once
believed that the RnRnRnRn combination was lethal, the existence
of homozygous roans proves this
wrong.
Many homozygous roan embryos are absorbed during their
early stage of development. Because such offspring are rare,
they are being lost somewhere,
most likely before they become
developed.
Contrary to popular thought,
roan-to-roan crosses do not produce lethal white foals.
Kelly Haberman, a Paint Horse
breeder in Asotin, Washington,
was concerned when she considered breeding two red roans
because she had heard the cross
could result in a lethal white.
Color changers
Roan horses are different, to be
sure. Because extremely roan
horses have a large amount of
white hair, they are often confused
with white or gray horses.
But while the roan gene covers
specific parts of the body with a
light coating of white hair, the
white gene (W) completely covers
the body with an even, white coat.
The gray gene (G) causes a light
sprinkling of white hair over the
entire coat, which becomes lighter
as the horse grows older. Eventu-
Want to know more?
If you would like to learn more
about the wonderful world of roan
genetics, the following books and
pamphlets can help:
• Equine Color Genetics by Dr.
D. Philip Sponenberg. Published
by Iowa State University Press in
1996. To order, call (800) 8626657.
• Horse Genetics by Dr. Ann T.
Bowling. Published by Oxford
University Press in 1996. To
order, call (800) 445-9714.
• American Paint Horse Association’s Guide to Coat Color Genetics and APHA’s Guide to
Registration. To order, call APHA’s
24-hour forms request line at
(817) 834-2742, extension 271.
• Horse Color Explained by
Jeanette Gower. Published by
Trafalgar Square Publishing in
2000. To order, call (800) 4234525.
• The Color of Horses by Dr. Ben
K. Green and paintings by Darol
Dickinson. The sixth edition of
the book, which was first published in 1974, was printed by
Mountain Press Publishing Company in 2001. To order, call (800)
234-5308.
K.C. MONTGOMERY
But after talking with equine
genetics experts at the University
of California–Davis, she bred her
1998 red roan stallion, Mr Irresistable Kid, to Barlink Cupie Doll,
his red roan grand dam.
Now, Kelly and her husband,
Mike, are awaiting the foal’s birth.
The couple became interested in
roans when they purchased Barlnk
Barb Bea, another red roan mare,
in 1997.
“We fell into the roan coloring
when we bought Barlnk Barb Bea,
who had been bred to Mr Kid Clue
(AQHA),” Kelly explained.
“We were not breeding for a
roan, but now that we have one,
we’re thrilled.”
When Mr Irresistable Kid was
born, Kelly was told that red roans
are the most difficult color to show
in halter because their muscles
can’t be seen as clearly, due to their
coat color.
Mr Irresistable Kid proved the
other breeders wrong.
The 4-year-old quickly earned a
Superior in halter, stood Grand 30
times and won 16 Reserves. In
addition, he won the Oregon Paint
Horse Breeders Triple Crown
Futurity as a yearling and was the
Northwest Coordinating Committee’s Reserve High-Point Halter
Stallion All Ages in 2000 and 2001.
“When he comes into the pen,
his muscles just bulge,” Kelly said.
“You can see them from the stands.
“Is he hard to show because of
his color? No. He really stands out
from the crowd.”
Blue boy: Mr Good And Plenty is a good example of a blue roan because he
has a uniform mixture of white hair on black.
ally, the animal turns completely
gray or white.
A foal may appear roan at birth,
or the color may become apparent
after the baby sheds its foal coat.
But roans do not become progressively lighter with age, as do gray
horses. Instead, some roans
become darker with age.
When a roan’s hair regrows over
a wound, the hair often doesn’t
come back in as white, so scars and
brands are readily apparent, making many roan owners protective of
their horses’ coats.
Roans change color according to
the season. They are lightest in
spring, when they shed their winter coats. They are more mediumcolored in summer. In winter, they
sometimes become so dark they
don’t look like a roan.
In fact, these seasonal changes
led to the Icelandic term for roan—
litförótt—which means “always
changing color.”
“I love owning a roan,” Kelly
Haberman said.
“I put about 12,000 miles a year
on my truck hauling to shows, and
I seldom see another red roan in
the show ring.
“It’s fun owning a horse of a different color.” s
PAINT HORSE JOURNAL
◆
JANUARY 2002
◆
111
2/5/04
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Page 1
BY FRANK HOLMES
DAVID PAYNE
Tovero
2/5/04
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Page 2
When a tobiano Paint is
crossed on an overo, a
“war of the genes”takes
place. The results are
often interesting, and
sometimes amazing.
Will the foal be a
tobiano or an overo?
Or will it be, like
Cajun Eclipse, the horse
pictured here, a little of
both? How can one
Paint Horse look so
different on opposite
sides you ask? The
answer is spelled
T-O-V-E-R-O.
DAVID PAYNE
Tovero
2/5/04
4:27 PM
Page 3
lthough the word “tovero”
has been a part of the
APHA’s vocabulary from
the onset of the registry, it remains
to this day somewhat of an ambiguous term.
What exactly is a tovero? Where
does it come from? What are its
physical characteristics? Where do
toveros rank on the Paint scale of
color production? Good questions,
and worthy of some investigation
and discussion.
A
What is a Tovero?
For the record, when a mating
between a tobiano and an overo
Paint produces an offspring that
exhibits characteristics of both patterns, the APHA recognizes the
resulting pattern as tovero. (It
should also be noted that, while
considerably rarer, a cross between
a tobiano and a solid can also produce a tovero. Examples of both
cases will be documented in this
article.)
Just as there are extremes within
the tobiano and overo coat pat-
tern—from mostly dark to mostly
white—so are there extremes
within the tovero pattern.
At one end of the spectrum—the
mostly dark one—are those toveros
that closely resemble tobianos
except for their face markings,
which show an overo influence. At
the opposite end—the mostly
white one—are those toveros
whose only dark pigmentation
might appear around the ears, eyes
or chestnuts!
In between those two extremes is
the horse that can be termed the
“typical” tovero, distinguished by
one or more of the coat characteristics shown in Figures 1 and 2.
A Horse of Another Color
There are Paint Horse families
that have consistently thrown
toveros over the course of the past
30 years. By studying these families
and their production records, a
clearer understanding of the pattern’s physical characteristics and
reproductive tendencies can be
gained.
Before we take a look at any
tovero horses or families, however,
the point must be made that the
examples that follow represent but
a small portion of the tovero horses
and tovero lines that exist. They
were chosen for use because they
illustrate the points made in this
article.
Beginning the study at the
darker, or tobiano-looking, end of
the tovero spectrum affords the
opportunity to make an observation on the identification of toveros
for registration purposes.
Identifying the tovero pattern is
not an easy task. During the association’s early years, some toveros
were mistakenly classified as
tobianos or overos.
In defense of the people who misclassified those animals, two points
must be made. First of all, during
the registry’s infancy, the pattern
was much rarer than it is now.
There simply weren’t enough
toveros being registered to establish
a workable profile of what their
physical characteristics were.
Two Typical Toveros
BY MICHELLE
Tovero
Figure 1—Top Of The Moon, sired by an overo and out of a
tobiano.
Figure 2—Skip Three, sired by a Quarter Horse and out of a
tobiano.
1. Dark pigmentation around the ears, which may
expand to cover the forehead and/or eyes.
4. Chest spot(s) in varying sizes. These may also
extend up the neck.
2. One or both eyes blue.
5. Flank spot(s) ranging in size. These are often
accompanied by smaller spots that extend forward across the barrel, and up over the loin.
3. Dark pigmentation around the mouth, which
may extend up the sides of the face and form
spots.
132
PAINT HORSE JOURNAL
6. Spots, varying in size, at the base of the tail.
DECEMBER 1997
Page 4
J BAR D STUDIOS
4:27 PM
LEROY WEATHERS
2/5/04
LEROY WEATHERS
Tovero
Figure 3—Gallant Ghost, sired by a tobiano
and out of a Quarter Horse mare.
Figure 4—Gallant Silhouette, sired by Gallant Ghost and out of a tovero.
Figure 5—Tru Bruiser, sired by a tobiano and
out of a tobiano.
Secondly, it had not yet been
firmly established how these
horses would breed—what patterns they would produce that
would prove or disprove their classification.
Thirty years of association
growth has alleviated both of these
conditions, and the APHA registration department now has the situation well in hand.
Let’s look at one of those early
cases of mis-classification.
his face was mostly solid, his right
eye was blue.
From a historical perspective,
although Gallant Ghost’s sire and
grandsire both had bald faces there
were no known overos in this Paint
family.
As a sire, Gallant Ghost is credited with 255 foals. Of these,
approximately 55 percent were
tobianos, 15 percent were overos or
toveros, and 30 percent were solid.
His siring record, then, classifies
him not as a tobiano, but as a tovero
with a strong tobiano influence.
It is interesting to note that when
the blood of Tinky’s Spook was
intensified, as it was when Gallant
Ghost was bred to the Tinky’s
Spook daughter Silly Filly, classic
toveros such as Gallant Silhouette
(Figure 4) were produced.
Painted Tru Tru, and out of a black
tobiano, Lily Quadrille, Tru Bruiser
was classified by the APHA as a
tobiano.
Color-patternwise, however, he is
extremely similar to Gallant Ghost.
From the throatlatch back, there is
no doubt that Tru Bruiser is a
tobiano (Figure 5). But, like Gallant
Ghost, when it comes to Tru
Bruiser’s face markings the lines
between the two primary Paint patterns begin to blur.
Viewed from the left, the stallion’s white marking covers twothirds of his face. It almost
surrounds his eye and covers the
jaw. In addition, both eyes are blue.
Is he then, like Gallant Ghost, a
mis-identified tovero?
To date, Tru Bruiser has sired 115
registered foals, including 110
tobianos and four toveros. Of the
toveros, three are out of overos and
the fourth is out of a Breeding Stock
mare from a strong overo background.
Given this record, it appears, face
markings to the contrary, that Tru
Bruiser is a true tobiano and properly classified.
A Bald-Faced Identity Crisis
Gallant Ghost, a 1972 bay stallion
by Peppy Spook by Tinky’s Spook
and out of Bold Farina AQHA, was
bred by Lyle and Butch Wonderlich
on their RoseAcre Farm near Idaho
Falls, Idaho.
A highly-successful show horse
and the breed’s 29th Supreme
Champion, Gallant Ghost was registered as a tobiano.
From his throatlatch back, he
was a textbook tobiano (Figure 3).
On the left side of his face, however, the big bay stallion sported a
great deal of white. In fact, if
viewed strictly from the left, his
face bore the look of a typical
tovero, complete with ear and forehead bonnet, eye spot and mouth
spot. And, while the right side of
Identity Crisis, Part II
To illustrate the degree of difficulty involved in typing this Paint
coat pattern, we need look no farther than to a modern-day Gallant
Ghost look-alike.
Tru Bruiser, a 1989 black stallion,
was bred by Forrest Nelson of
Meeker, Colorado, and is owned by
the Polo Ranch of Big Horn,
Wyoming and Marietta, Oklahoma. Sired by a black tobiano,
PAINT HORSE JOURNAL
DECEMBER 1997
Hi Color
One of the most potent toveroproducing Paint lines of all time
133
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Page 5
COLOR-WISE
Skippa Rope’s get, by
color pattern, out of 82
Quarter Horse mares.
}
Skippa Rope
MARGE SPENCE
Tobiano (41)
Overo (36)
Tovero (0)
AQHA mare
Solid (5)
originated in south-central Colorado, and descended from Hank
Wiescamp’s foundation tobiano
sire, Skip Hi. To begin our study of
this line, let’s look at one of Skip
Hi’s best-known sons, Skippa
Rope.
Foaled in 1968, this APHA Champion stallion was out of Baby Doll
McCue, a cropout who traced on
both sides of her pedigree to that
potent source of cropout color, Old
Fred.
Classified by the APHA as a
tobiano, Skippa Rope was marked
in a variation of the typical tovero
pattern (Figure 6).
He was a predominantly white
horse with the traces of a red roan
ear bonnet. On the left side of his
face was a large spot that began at
eye level and extended down to
134
Figure 6 (top )—Skippa Rope, sired by a
tobiano and out of an overo. Figure 7
(above)—Sullivan’s Heathen, sired by Skippa
Rope and out of a Quarter Horse mare. Figure
8 (left)—Fly Skip Fly, sired by Skippa Rope
and out of a Quarter Horse mare.
BY MICHELLE
Tovero
cover the jaw. On the left side of his
mouth, he had a small, oblong spot.
On the right, Skippa Rope’s face
was without any dark pigmentation except for that around his ear.
In typical tovero fashion, he also
PAINT HORSE JOURNAL
DECEMBER 1997
had small, haloed spots on his
shoulder, barrel and loin areas, and
larger spots on the flanks.
Classification notwithstanding,
Skippa Rope proved to be a strong
tovero sire. From 18 foal crops,
Skippa Rope sired 139 registered
horses, including 59 overos, 74
tobianos, one tovero and five solids.
(Note: When discussing early
APHA sire records, it must always
be remembered that those records
may not be 100 percent accurate. As
an example, just because Skippa
Rope has only five registered
Breeding Stock offspring, that does
not mean that was all he sired. It is
2/5/04
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Page 6
possible that he sired additional
solids that were never registered.)
As is the case with the typical
tovero breeding horse, Skippa Rope
repeatedly sired both tobiano and
overo offspring out of Quarter
Horse mares (Figures 7 and 8).
The lesson to be taken from the
study of Skippa Rope is two-fold.
First, there appears to be a strong
correlation between his physical
appearance, which favored the
overo side of his family more than
the tobiano side, and his production
record. Simply put, he looked more
like an overo than does Gallant
Ghost, and he sired a much higher
percentage of overos and toveros
than did Gallant Ghost.
Second, and this observation is
far more open to discussion than
the first one, there appears to be a
correlation between the amount of
white a tovero has, and the percentage of Paint color the animal produces. Mostly-white Skippa Rope
had a 96 percent color rate.
To further illustrate this phenomenon, let’s take a look at two additional mostly white stallions from
this same line.
and two large haloed spots at the
base of his tail.
As a sire, Skip A Shay put 113
foals into the APHA registry of
which 86, or 76 percent were colored.
Skip A Silver, a 1978 full brother
of Skip A Shay, was a basically
white horse, with just an ear bonnet
for color (Figure 9). Classified by
APHA as a tovero, he is credited
with 101 registered foals. Ninetytwo of these, or 92 percent, were
colored. Like both Skip A Shay and
Skippa Rope, Skip A Silver proved
time and again that he could sire
both tobianos and overos out of
Quarter Horse mares (Figures 10
and 11).
Between them, Skip A Shay and
Skip A Silver sired 214 registered
foals, of which 178, or 83 percent,
were colored.
Apparently, when it comes to
toveros and their ability to produce
color, white is where it’s at.
Not convinced? How about a few
more examples?
Don’t Skip the Color
Hank-A-Chief, a 1969 tobiano
stallion, was sired by Skip’s Lad, by
Skip Hi, and was out of Cherokee
Maiden.
One of the most popular sires of
his day, he sired 473 registered
foals, including 457 tobianos, 14
toveros and two overos.
It is possible that the number of
toveros is understated due to misidentification. Take the foals of
Skipa Lea for example.
Skipa Lea, a 1966 sorrel overo
cropout mare, was sired by Show
Cash AQHA and out of Anita
Venus AQHA. Here again, the Old
Fred influence comes into play with
Show Cash being 100 percent
Wiescamp-bred.
Skipa Lea was bred to Hank-AChief seven times, and registration
records reveal that she had five
tobianos and two tovero foals.
Skip A Shay, a 1975 son of HankA-Chief and Skipa Lea, was registered as a tobiano. His registration
photos, however, reveal him to be a
tovero with a medicine hat marking
THE PICTURE PLACE
Tovero
Figure 9 (top)—Skip A Silver, sired by a tobiano and out of an overo. Figure 10 (bottom
left)—Silver Sport, sired by Skip A Silver and out of a Quarter Horse mare. Figure 11 (bottom right)—Silver Sensation, sired by Skip A Silver and out of a Quarter Horse mare.
PAINT HORSE JOURNAL
DECEMBER 1997
135
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Page 7
COLOR-WISE
Easter Sunrise’s get, by
color pattern, out of 115
Quarter Horse mares.
Tobiano (54)
}
Easter Sunrise
Overo (20)
Tovero (21)
AQHA mare
Easter Outfits Anyone?
Easteriffic, whose tovero pattern is
similar to those pictured in Figures 1
and 2, has sired 53 foals to date.
Their numbers include 17 tobianos,
11 overos, 13 toveros and 12 solids
for a color percentage of 77.
Another older Paint line that consistently produced toveros is that
which originated with Easter Sunrise.
Sired by Grease Paint, a tobiano,
and out of Mendocino Belle, an
overo, Easter Sunrise was foaled in
1971. Basically a white horse, he
did have dark-pigmented ears, several small haloed spots on his face
and hip, and larger haloed spots
near the base of his tail (Figure 12).
After a show career that saw him
earn an APHA Championship and
three National performance titles,
Easter Sunrise went on to sire 167
registered foals. Of these 138, or 83
percent, were colored.
As a further example of his
potency, Easter Sunrise was bred
five times to a palomino Breeding
Stock mare named Koko. She was
sired by AAA AQHA Champion
stallion Leo Bingo, and out of a
cropout overo mare named Trophy
Girl. From this cross, four toveros
and one overo were produced. One
of the toveros is Easteriffic (Figure
13), the horse appearing on the Journal’s cover this month.
While the well-known overo stallion Gambling Man (Figure 14),
owned by Al Reece of Santa Ynez,
California, is a predominant sire of
overos, APHA records do credit
him with putting nine tobianos and
16 toveros into the registry. Close to
one-fourth of those 25 horses just
happen to be out of one mare—7-L
Siemon (Figure 15).
Foaled in 1977, 7-L Siemon was
sired by Snip’s 7L Bar, an overo, and
out of Pat Skipper Siemon, a tobiano.
Her registration records show her to
be a tobiano, but photographs reveal
her to be a typical tovero.
After being shown for a number
of years, 7-L Siemon was retired to
the broodmare band and bred 11
times to Gambling Man. Her fullsibling production record to date
tallies one tobiano, four overos, five
toveros and one solid.
136
PAINT HORSE JOURNAL
Not a Gamble After All
DECEMBER 1997
DARRELL DODDS
Solid (20)
STEVE DIGINO
Tovero
Figure 12 (top)—Easter Sunrise, sired by a
tobiano and out of an overo. Figure 13
(above)—Easteriffic, sired by Easter Sunrise
and out of a Breeding Stock mare.
One of her tovero offspring is
Kenny Rogers (Figure 16), foaled in
1988 and currently owned by Ann
Cumming of East Lyme, Connecticut.
Color-patternwise, Kenny Rogers
is identical to Skip A Silver—white
with a medicine hat bonnet and two
blue eyes. Used sparingly at stud,
he has sired 31 registered foals to
date. Included among them are
2/5/04
4:27 PM
Page 8
eight tobianos, nine overos, 10
toveros and four solids. This
equates to 84 percent color.
His record further includes siring
all three color patterns out of
tobiano, overo and Quarter Horse
mares (Figures 17 and 18).
Again, the historical data appears
to demonstrate a correlation
between the amount of white
toveros sport, and their color-producing percentages.
For another example, let’s take a
quick look at an almost totally
white horse who was given a most
appropriate name.
The Ghost with the Most
Figure 14—Gambling Man, sired by a Quarter Horse and out of a Quarter Horse mare.
1968 out of the overo mare Slip
Along W.
From the standpoint of his coloring and sire record, Brujo is unique,
even for a tovero.
Bred by Wiescamp and sold as a
yearling to Joe Taylor of Moab,
Utah, Brujo was initially inspected
for registration in March of 1972 by
“Hoot” Walker of Wichita Falls,
Texas. In his report, Walker noted
that he would “pass this horse for
breeding only. He has no color.”
Time, and an extensive siring
record on the part of Brujo, proved
Walker to be incorrect.
From the first 36 foals that he
sired, 50 percent of which were out
of Quarter Horse mares, Brujo sired
17 overos, 12 tobianos, six toveros
and one solid. The lone solid offspring, Lecheria, was a white mare
foaled in 1974.
Out of Mrs. Thayn, an overo
mare of unknown bloodlines,
Lecheria went on to produce seven
registered foals—six overos and
one solid. Of her six colored offspring, three were sired by Quarter
Horses.
Brujo was eventually reinspected, found to have dark pigmentation around both eyes and a
small spot on his right side, and
was re-classified as a tovero. He
sired 116 foals during his lifetime,
of which 105 were colored.
Of Brujo’s 11 solids, five were
listed as white. Of those five, four
had offspring, and of those four,
three produced overo color when
crossed with Quarter Horses.
It appears that history has proven
Brujo to be one potent tovero.
Figure 15—7-L Siemon, sired by an overo
and out of a tobiano.
Figure 16—Kenny Rogers, sired by Gambling Man and out of 7-L Siemon.
Mack-Attack
In 1984, Brujo was bred to a red
dun, double-bred Three Bars (TB)
Quarter Horse mare named Leta
Bar Ann. In 1985, she produced a
DON TROUT
Paying another visit to the
Wiescamp family of Paints, we
come upon a son of Skip’s Lad
named Brujo (Figure 19).
Brujo (which is pronounced
Brew’ ho, and is Spanish for
“devil” or “ghost”) was foaled in
GAIL BATES
Tovero
Figures 17 and
18—The get of
Kenny Rogers
out of Paint
Horse mares are
a study in contrasting patterns.
PAINT HORSE JOURNAL
DECEMBER 1997
137
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Page 9
COLOR-WISE
Brujo’s get, by
color pattern, out of 81
Quarter Horse mares.
Tobiano (10)
Brujo
}
Figure 19—Brujo, sired by a tobiano and out of an overo.
Overo (31)
Tovero (34)
AQHA mare
Solid (6)
GAIL BATES
Tovero
Figure 20 (top left)—Cajun Indio, sired by an
overo and out of a tobiano. Figures 21–23
(right)—Cajun Indio get out of Quarter
Horse mares. The top two foals are full
siblings.
solid white colt named Slipalong
Mack who has proven to be every
bit as much of an enigma as his
sire.
Unlike Brujo, Slipalong Mack had
no dark pigment around his eyes,
and no spots on his body. All he did
have was two small sorrel spots
surrounding the chestnuts on his
front legs.
Due to the fact that those spots
were not large enough to satisfy the
APHA registration requirements in
effect in 1985, Slipalong Mack was
classified as a Breeding Stock.
To date, the now-12-year-old stallion has sired 51 registered foals.
With 44 of his get being out of
Quarter Horse mares, the results
are 24 overos, 12 tobianos, eight
toveros and seven solids.
Due to the fact that the APHA
had classified him as a solid Breeding Stock Paint Horse, when his
first colored offspring out of solid
mares were being considered for
registration, their parentage was
verified. That process proved
beyond a shadow of a doubt that,
far from being a solid horse, Slipalong Mack was in reality a highlypotent tovero.
138
PAINT HORSE JOURNAL
DECEMBER 1997
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Page 10
Tobiano or Tovero? You Make the Call.
NEWMAN PARKER
Tovero
Had enough?
Before we wrap up our historical
and visual investigation of the
tovero Paint Horse, let’s take one
last look at what should now be recognizable as a typical representative of the genre.
intriguing about the entire tovero
phenomenon.
Expect the Unexpected
With a Paint tovero breeding animal, the catch-all phrase could be,
“expect the unexpected.”
To briefly summarize, toveros
most commonly occur when tobiano
and overo Paints are crossed.
Toveros come with six basic coat
characteristics, which may be present in differing combinations and
configurations.
Toveros appear, depending on
their patterns, to have the ability to
consistently sire Paint color at the
rate of 80 percent and higher, bred
to either tobiano, overo or solid
mares.
When compared to the attention
that has been lavished on the tobiano
and overo coat patterns over the
years, the tovero pattern is a relatively-unexplored one. There is
much yet to investigate and, hopefully, learn from.
One thing is for sure.
With their widely varied color
patterns, which often encompass
the most appealing aspects of both
the tobiano and overo patterns, and
their proven propensity to sire
every Paint pattern known, toveros
are genetic goldmines whose colorproducing potential is just beginning to be understood and
appreciated.
Cajun Cookin’ Anyone?
Cajun Indio (Figure 20), owned
by Linda Clark of Newberg, Oregon, is a blue roan tovero foaled in
1983. “Cajun” was sired by Cajun
Joe Jet, a cropout overo, and is out
of Indio’s Snowbird, a tobiano.
With 110 registered foals to date,
Cajun Indio’s get record includes
90 colored get (Figures 21–23), for a
color rate of 81 percent.
Bred six times to the cropout
overo mare Maid Of Roses, Cajun
Indio sired two tobianos, one overo
and three toveros. One of the
toveros is Cajun Eclipse, whose
opposite-sided head shots appear
at the beginning of this article.
Owned by Lesa and Lars Mandt
of Montague, California, “Eclipse”
has already established the potency of his tovero gene. With only
17 get to his credit to date, primarily out Quarter Horse mares, he
has sired tobianos, overos, toveros
and solids.
In doing so, the colorful young
Paint stallion sums up what is most
And the Answer is...
Although Skip On Seven looks very much like a tobiano when viewed from his right, he looks
entirely different when viewed from his left. A double-bred Skip’s Lad horse, he was the sire
of 97 registered foals. Overall, he had an 83 percent color production rate. Bred to 70 Quarter
Horse or Thoroughbred mares, he sired 35 tobianos, 19 overos, four toveros and 12 solids. His
production record, then, leaves no doubt that Skip On Seven was a classic tovero.
PAINT HORSE JOURNAL
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139
Get the real story on APHA’s newest coat colors and the discovery
of the champagne dilution gene.
By IRENE STAMATELAKYS
ature has a way of surprising us. Just
when we thought we had a good grip on
color genetics, we get thrown an equine
mystery—an unexplained and unusuallooking palomino, buckskin or dun;
pumpkin-colored, freckled skin; eyes that
shift from icy blue to hazel to amber. This list goes on, but
it’s enough to stump even the most experienced Paint
breeder. What color is this horse?
Fortunately, advances in science have solved this genetic
mystery, helping us better understand this rare and unique
phenomenon—the champagne. Researchers recently discovered the genetic mutation that causes the champagne
dilution, and a DNA test is now available to identify those
horses carrying the gene.
PAM CAPURSO
NN
And there’s another reason to celebrate. The American
Paint Horse Association (APHA) is the first Western breed
registry to officially recognize the amber, gold and classic
champagne colors.
“Not just any pretty color”
“Champagne is not just a coat color,” said Carolyn
Shepard, president and registrar of the International Champagne Horse Registry (ICHR). “Champagne is a specific
gene causing a dilution of skin, eyes and hair, and is from
distinct pedigree lines. It’s not just any pretty color.”
One of the founding members of the ICHR, Shepard
has researched champagne characteristics and pedigrees
extensively and works passionately to make sure that what
the public learns about champagnes is accurate.
MICHELE JORGENSON
Champagnes often sport a darker hair coat
in winter than in summer, the reverse of most
other coat colors. They sometimes have shiny,
iridescent coats. However, shine is not unique
to champagnes.
Reverse dappling, with darker centers
and lighter edges, is another champagne
trademark, although this has been found in
other colors as well.
Eye color is one of the most striking
champagne traits in foals and young horses.
They are born with icy blue eyes that turn
green around the edges and then amber as the
foals age. While many adult champagnes have
amber eyes, some darken to brown.
All champagne foals are born with bright
pink skin, with the freckles developing later.
COURTESY LAURIE RODEN
“Champagne is a color-modifying gene like
cream or dun and not a term for shiny, light or
strangely-colored horses,” wrote Shepard.
In addition to changing a horse’s base
coat, the champagne gene also produces
distinct characteristics that allow us to
differentiate champagnes from other creamrelated colors.
There are four colors in the champagne
spectrum: amber, gold, classic and sable.
An amber champagne results from the
champagne gene acting on a bay base coat.
This is best described as golden tan with
brown points, with the mane and tail often
darker than the legs. These horses are
frequently misclassified as buckskins.
The gold champagne horse is produced
when the champagne gene acts on a chestnut
or sorrel base coat. The body color is golden,
and the mane and tail may be flaxen or
gold-toned. These horses are usually mistaken
for palominos.
The classic champagne horse is the result of
the champagne gene acting on a true black
base coat (without an agouti gene). This rare
color is difficult to describe, but has been
called dove gray, chocolate or lilac dun. These
horses are often registered as duns, smoky
blacks or grullos.
The sable champagne horse is also a rare
shade, produced when a champagne gene acts
on a seal brown base coat (with the agouti-t
gene). Sables look very much like classic
champagnes as adults, and sometimes the only
way to differentiate the two is by testing for
the agouti-t gene. These horses are commonly
registered as duns or grullos. [Note: sable
champagne is not recognized as an official
APHA color.]
Other rare variations can be created when
you mix champagne with other dilute genes,
such as dun or cream.
In addition to coat color, champagnes are
also identified by these traits: pink skin with
dark freckles, darker coats in winter than
summer, reverse dappling and, in foals,
bright pink skin with blue eyes and darker
coats.
All champagne horses have pinkish skin
under colored hair with dark freckles. Not to
be confused with the pale, unpigmented skin
found under white Paint markings, champagne pink skin has pigment. It’s been
described as pumpkin- or salmon-colored.
This light, freckled skin is found everywhere,
but is easiest to identify around the eyes,
muzzle, external genitalia and udder.
Below: California
Champagne is a rare
sable champagne
produced when a
champagne gene
acts on a seal brown
base coat (with the
agouti-t gene).
Bottom: Gold
champagnes,
frequently mistaken
for palominos, are
produced when the
champagne gene
acts on a chestnut or
sorrel base coat.
Sable champagne
Gold champagne
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What do you get
when a champagne
gene dilutes a black
base coat? A classic
champagne, like Dun
In Champagne
(bottom).
A dilution gene like no other
D. Philip Sponenberg, PhD, Ann Bowling,
PhD, and Liz Nutter were the first to document the champagne colors and dilution gene
in literature in 1996. They correctly identified
the champagne gene as dominant, diluting
black to brown and red to yellow. Whether the
foal inherited one or two copies of the gene, it
would express the champagne phenotype.
In 1999, at the University of Kentucky’s
Gluck Equine Research Center, Rebecca
PAM CAPURSO
Amber champagne
Classic champagne
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PAINT HORSE JOURNAL
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COURTESY CARLA BATES/TRISH JOHNSON
When the
champagne gene
dilutes a bay base
coat, you get an
amber champagne,
like Ima Frosted
Chloe (below).
Many of these foals have a darker first coat
that lightens as they shed out.
Researchers say champagnes do not have
special health issues, such as a tendency
to sunburn or the melanomas that plague
gray horses.
OCTOBER 2008
Bellone, PhD began collecting blood samples
from champagne horses to search for the
genetic mutation causing the dilution. Samantha Brooks, PhD later joined her, and together
they worked under the guidance of Ernest
Bailey, PhD, collecting families to study and
conducting genetic testing. [Note: Dr. Brooks
is responsible for the discovery of both the
Sabino 1 gene and the tobiano gene.]
Champagne Paint enthusiast Pam Capurso
first submitted a proposal to the APHA
Registration Committee in 2001 requesting
recognition of the champagne dilution gene
and the resulting coat colors on an equal basis
with the dun and cream dilution genes.
In 2003, the APHA Registration Committee decided to acknowledge the champagne
dilution gene to a limited extent. At an
owner’s request, the Registration Department
would add the remark “appears to carry the
champagne gene” to a horse’s certificate.
However, champagne horses continued to be
registered as palominos, buckskins and duns,
as the committee was not prepared to officially
recognize the champagne colors until a genetic
test could prove the gene’s existence.
Eventually, the project caught the attention
of Deborah Cook, a graduate student at the
University of Kentucky. Cook was on rotation
in Dr. Bailey’s immunogenetics lab in January
2007 when she was assigned the champagne
research project to learn the basics of
molecular work.
“I learned the PCR process [polymerase
chain reaction is a technique widely used in
molecular biology] and how to do the marker
mapping,” said Cook. “I took it a step further
and I got addicted to it.”
Using three families of champagne horses—
two were Tennessee Walking Horses and the
third was a Paint Horse family—Cook
mapped the gene’s location by comparing genetic markers of heterozygous stallions with
their offspring, half of which were champagne
and half of which were not. Genetic
sequencing then led to the discovery of the
champagne dilution mutation.
“I thought I was getting close early in the
summer,” recalled Cook, “and I found it in
October 2007.”
Also remarkable was the discovery that the
champagne dilution was caused by a
completely different gene on a different
chromosome than the other dilution genes—
cream, dun, pearl and silver.
Next, a molecular test for the champagne
dilution gene was developed and verified by
While the champagne dilution gene is a
recent discovery, one family of champagne
Paints traces all the way back to Gold Bonnet,
a 1964 tobiano mare registered as a palomino,
but more than likely a gold champagne.
Bred by Howard Quillin of New Sharon,
Iowa, the mare was by Red Ball Baby, a bay
Quarter Horse stallion, and out of Queen, an
unregistered Paint mare. Pam Capurso of
Brooksville, Maine, has extensively researched
these bloodlines and says that Queen was a
Waggoner mare that Quillin picked up at an
auction in Pennsylvania. The champagne
dilution gene in stock horses traces back to the
Burnett Ranch in Iowa Park, Texas, and the
Waggoner Ranch in Vernon, Texas.
Gold Bonnet’s original owner was Don
Allgood, also of New Sharon, Iowa. As the
story goes, he unknowingly perpetuated this
line of champagne Paints, breeding Gold
Bonnet and producing five registered
offspring, and among them, four champagnes.
Three of her daughters—Gold Zip, Jr’s Honey
Moon and Jr’s Goldigger—together produced
17 champagne Paints.
The Gold Bonnet line continued, and
mares accounted for most of the generations
that followed.
The family tree eventually leads to Good
Gold Almighty, a 1996 homozygous tobiano
stallion registered as dun, but who was
CRISTIN CONNER
COURTESY LAURIE RODEN
Champagne made in Iowa
Blue eye color
Hazel eye color
COURTESY LAURIE RODEN
testing more than 200 champagne horses in
12 breeds. The genetic test became available
commercially in early July, first through the
University of Kentucky and shortly after at the
University of California-Davis and other
DNA testing labs.
Finally, breeders had a tool to distinguish
the champagne gene from other hair dilution
genes and correctly identify this coat color.
“The champagne message boards online are
just buzzing with people getting test results,”
said Cook, who owns four Paints.
The peer-reviewed paper on this study was
scheduled to appear on-line in the September
19th issue of PLoS Genetics.
True to their word, the APHA Registration
Committee officially accepted the gold, classic
and amber champagne coat colors at the association’s annual Workshop meeting in June.
At press time, four horses have been registered
as champagnes, the first being Raffelschampagnewish, a 2-year-old solid champagne
stallion owned by Ned and Barby Stewart of
Celeste, Texas.
Amber eye color
actually a classic champagne. Gold Bonnet is
in the fourth generation of his pedigree.
Making his way from Massachusetts to Maine
to Arizona to Washington, Good Gold
Almighty introduced many people to the
champagne coat color. Along the way he sired
24 registered Paints, with about 16
champagnes among them, before he died in
2006. Good Gold Almighty and his offspring
were one of three families used in the
University of Kentucky’s research to locate the
champagne dilution gene.
Today, Gold Bonnet has more than 56
champagne Paint descendants, including
Champagne foals
are born with
icy blue eyes that
turn hazel green
around the edges
and then amber as
the foals age.
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COURTESY LAURIE RODEN
COURTESY CAROLYN SHEPARD
COURTESY LAURIE RODEN
This light, freckled
skin is found
everywhere on a
champagne,
but is easiest
to identify around
the eyes, muzzle,
external genitalia
and udder.
Peppy Digger, APHA Champion and earner
of 492 APHA points. The number of
champagne Paints is growing annually, as
breeders continue this family line and
outcross to Quarter Horses with the
champagne dilution gene.
Carrying on the tradition
In 1986, Richard and Marcia Ratliff of
Rocking R Paints in Albia, Iowa, purchased
Gold Moon, a gold champagne granddaughter of Gold Bonnet who the next year
produced Golden Frost. She in turn
produced seven champagne Paints out of
nine foals.
In the beginning, with each new foal, the
family would argue what color the foal was.
Capurso, who has done extensive research on
the Gold Bonnet line, explained that when
Golden Frost’s second foal, Ace Junior, was
born, they were delighted because they were
sure he was a black and white tobiano.
“Champagnes are born darker and then
shed out lighter, so you can just imagine their
surprise when he shed out to be a classic
champagne,” Capurso said.
Today at Champagne Acres in Albia, Iowa,
Trish Johnson and her daughter Carla Bates
are carrying on the Gold Bonnet family line.
Johnson was so taken by the horses’ unusual
and attractive coloring that she couldn’t bring
herself to sell them. Instead, she built a
champagne broodmare band.
“Mom raised 26 champagnes out of those
mares and had a grand total of 32,” recalled
Bates. “She still has Illusion Farm Champ, a
classic champagne tobiano stallion by Good
Gold Almighty, and five champagne mares,
including My Champagne Streke, a granddaughter of Q T Poco Streke.”
According to Capurso, the family played an
active role in raising awareness of the
champagne dilution and supporting the
efforts to get APHA to recognize the color.
On the West Coast, Carolyn Shepard also
breeds champagne Paints in Paso Robles,
California, in addition to her duties as ICHR
president. Among her 13 Paints, she has seven
champagnes, including a stallion named
California Champagne. “Fred” is a 6-year-old
sable champagne tobiano by Good
Gold Almighty.
Today, California Champagne stands at
JMJ Stables in Graham, Washington.
“When Good Gold Almighty died, his
owner [Michele Jorgenson] needed someone
to take his [breeding] book, so I leased Fred
to her,” said Shepard. “He has been making
little champagne Paints in Washington for two
years now.”
To date, Fred has sired 13 registered Paints,
including a 2008 champagne tobiano filly
named Carolina Champagne.
Resources
International Champagne Horse Registry—www.ichregistry.com
Champagne Horse Breeders’ & Owners’ Association—www.chboa.com
University of Kentucky Equine Parentage Testing & Research Lab
www.ca.uky.edu/gluck/EPTRL.asp
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OCTOBER 2008
More
genetics
Look for an article on newly
discovered scientific information on cream genetics in the
December Paint Horse Journal.
Docs Golden
Champagne sports
reverse dappling,
with darker centers
and lighter edges,
found frequently in
champagne horses
(below).
Many champagne
foals are born with
a darker coat that
lightens as they
shed out. Yes, this is
the same horse!
Courgandbynumbers
(center, name
pending) with his
dam at birth and
three months later
(bottom), is a gold
champagne.
COURTESY NATALIATATE AND
JORDAN PIERCE
equine mysteries. It’s unknown how many
owners will request color corrections for their
misclassified palominos, buckskins, and duns.
And while Cook has finished her champagne research at the University of Kentucky,
she says that there may be future work if people are interested in the origin of the dilution.
From the new genetic test to official recognition of the color, several Paint breeders
across the country are ready for the horse
world to join them in a champagne toast.
“This particular dilution is very rare,” said
Capurso. “The horse market is soft right
now—champagne might give it a shot in the
arm if somebody is looking for something
different. I urge anyone who owns a
champagne horse, or is considering adding the
color to his or her stable, to have the horse
genetically tested.” s
COURTESY AUDRA DURHAM
While champagne Paints are still a relatively
rare phenomenon, word is spreading fast and
the color is growing in popularity, says breeder
Laurie Roden. She has been getting calls from
as far away as Europe from interested buyers.
Roden founded ChamPaint Equine, a small
breeding and show facility in Phoenix,
Arizona, with the hope of producing highquality halter and performance horses that are
champagne Paints.
In 2006 she bred her amber champagne
mare, Miss My Diamonds AQHA, to Fleet
Attraction. The cross produced Korbel, a
2007 amber champagne overo stallion
destined to become ChamPaint Equine’s
foundation sire. Korbel’s color traces back to
My Skip Vanzi, a gold champagne Quarter
Horse stallion who also carries the dun gene.
Roden attributes the increased interest in
champagne horses to the ICHR, one of two
color registries working to register horses
carrying the champagne gene, promote those
horses and educate horse owners about the
genetics behind the color.
“The ICHR is really promoting it and
doing stallion service auctions, which helps,”
said Roden, who has registered five of her
horses with the association.
Shepard spearheaded the foundation of the
ICHR in 2000.
“There are 165 current members and about
615 horses registered,” said Shepard. “Of
those horses, 65 are registered Paints. There
are about 20 different breeds or crosses in the
registry. Our highest number of registered
horses are Quarter Horses, followed by
Miniature Horses, Tennessee Walking Horses
and then Paints.”
The Champagne Horse Breeders’ &
Owners’ Association (CHBOA) was founded
in 2005 and has about 175 registered
horses, although currently none are Paints.
Nevertheless, the CHBOA offers a wealth of
information on its Web site about champagne
color genetics.
Mystery solved?
COURTESY AUDRA DURHAM
“A horse doesn’t become a champagne just
because you can’t figure out what other color
it might be,” said Shepard. “The point that
people keep missing is that champagne is not
just a coat color. If their horse has pitch black
skin, there is just no way it’s a champagne.”
Luckily, the new genetic test makes it much
easier for breeders to accurately determine
whether a horse is a true champagne. No
doubt, this tool will help solve a number of
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By Irene Stamatelakys
How can you tell the difference between a dun and a
similar shade? If a horse has a dorsal stripe, doesn’t that make it a dun?
Can a buckskin have a dorsal stripe?
Can dun markings fade with time? These
are just a few of the questions our experts
have fielded over the years.
Genetic Evidence
“Dun is a dominant gene in the dilution category,”
explained Julia Lord, a Paint breeder in North Liberty,
Indiana.
A variety of colors can resemble dun, making it one of the
most frequently misidentified coat colors.
Like the tobiano
gene, a foal only needs
to receive one dun gene
from its parents to express the dun phenotype on any base color.
“Because it is dominant, it cannot skip
generations,”
said
Lord. “A dun horse
must have at least one
dun parent.”
This allele, named
D, is located at the
dun locus. The dun allele lightens both red
and black pigment
equally, except for
black points on the
legs, mane and tail. It
has no effect on skin
pigment or eye color.
Visually, heterozygous and homozygous duns look identical.
In his book Equine Color Genetics, D. Phillip Sponenberg, DVM, PhD, wrote, “the dun allele causes black on
the body to be lightened to a slate blue grey or beige, and
red on the body to be lightened to tan (on bays) or light
red (on chestnut). It tends to leave points unaffected, as
well as leaving the head darker than the body.”
There’s more to dun than just diluted body hair, says
Cecilia Penedo, PhD, who is actively researching the dun
gene at the Veterinary Genetics Laboratory at the University of California-Davis.
“The display of the darker
‘primitive marks’ is an associated
characteristic of dun,” said Penedo.
What confuses people is that
some duns have very minimal
primitive marks, but some nondun can have them too, although
the marks in those cases are usually fainter.
The dun palette
Surprisingly, dun dilutes make
up only 4.5 percent of all registered Paints. Of the nearly 1 million horses registered by the
American Paint Horse Association (APHA), there are approximately 20,600 red duns, 18,000
duns and 5,200 grullos in the
stud book. Not only are the colors rare, they are also challenging to identify.
All it takes is one dun allele to dilute a sorrel or chestnut
base coat into a red dun. They can range from a distinctive
light peach or apricot tone to a darker shade that could
pass for a sun-bleached chestnut. Points and markings are
generally a darker red but in some cases are very light and
difficult to see.
Add a dun dilution gene to a bay base coat and you have
a dun, also called bay dun, zebra dun or yellow dun.
Breeders say the shade is similar to peanut butter and that
duns tend to be more earth-toned than buckskins.
X
JESSICA HEIN
G R A P H I C S N J RW
K. BEER, COURTESY JONI VOLOSHIN
hat dilutes coat colors to shades that range from
apricot to peanut butter to olive? Here’s a clue.
These horses also sport dorsal stripes and other primitive
markings.
The solution to this mystery may be the dun gene. But
before you jump to conclusions, let’s examine the genetic
evidence. When is it dun? And when is it a look-a-like
impostor?
“There are a variety of horse colors that sometimes appear to be very similar to some of the dun colors,” said
Nancy Castle of Paradise, Texas, founder of duncentralstation.com, an educational Web site. “The most commonly confused ‘look-a-like’ color is buckskin, but buckskins are not the only color that can be confused with
the dun colors.”
The dun dilution gene creates three main colors: grullo,
Quanah Little T's color (above); red dun, as shown by
Painted Red Wren (right); and dun, the color of Gay Bar
Drummer (below).
JESSICA HEIN
W
JESSICA HEIN
The dun dilution gene can
fool you unless you know the clues
PAINT HORSE JOURNAL
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“Horses of various colors have been known to have a
visible dorsal,” said Castle. “But without the dun gene
diluting the coat, the horse is not a dun.”
The challenge comes in identifying the true dun dorsal
stripe. (See sidebar “The Great Imposter,” on page 78)
APHA FILE PHOTO
Also called primitive marks or dun factors, these characteristics are darker than the body color and essential to
distinguish duns from similar hues. The dorsal stripe, leg
markings, shoulder markings and concentric marks on the
forehead are four prime examples.
The dorsal stripe is
probably the best
known of the dun
factors. Kostelnik describes the dorsal
stripe as a clear,
sharp-edged line, not
an area of blurry
shading, running
along the spine.
“While the stripe
needs to have sharp
edges, it does not
A dun’s dorsal stripe is a clear, need to be unbrosharp-edged line of color down ken,” she said. “Also,
it can have bodythe horse’s spine.
76
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JESSICA HEIN
Dun markings
Leg markings–including barring, striping and mottling–
are dun factors typically found on upper legs and around
the knees and hocks.
“It certainly can be hard to tell a non-dun dorsal stripe
apart from a real dun dorsal stripe,” said Lord. “A nondun dorsal strip has a different ‘look’ and ‘character’ to it
than a dun dorsal stripe.”
Other dun factors include ear markings, a face mask and
frosting on the mane and tail.
While the dun dorsal has a sharp edge to it, the nondun dorsal has more of a tone-on-tone coloring, with the
stripe’s edge gradually fading into the body coat.
The next big dun clue is leg markings, also called leg
barring or zebra stripes. A wide variety of dun leg markings
are possible.
“Found primarily on the rear of the upper forelegs, these
may vary greatly from barring (like the rungs of a ladder),
to striping (like zebra stripes) to mottling (like sponge
painting),” said Kostelnik. “Other places to
WHAT DO YOU GET IF YOU
look for these markCROSS A DUN WITH A BAY?
ings are inside the
Find the answer for this or upper forelegs, on or
any other color combina- behind the knees,
tion with My Color Calcu- around the hocks, or
anywhere on the legs.”
lator, available with your
The third dun clue
APHA Plus subscription at is shoulder markings,
also called withers
aphaonline.com.
stripes,
shoulder
stripes, or a shoulder
shadow. This can be a clearly defined stripe, like the type
seen on donkeys, or a larger shaded area descending from
the mane.
Concentric marks, also termed cobwebbing or spiderwebbing, are the fourth major dun clue. These are concentric circles of dark hairs on the forehead.
Duns can have other markings such as ear markings
(dark ear rims, bars on the ears or light tips), frosting on
the outer edges of the mane and tail, dark shading or striping on the neck, and a dark face mask.
Experts generally agree that all duns will have a dorsal
stripe, if you can see it. White Paint markings can hide the
dorsal stripe, leg barring, or any other dun factor. Also, the
addition of other dilution genes, for example cream, could
possibly lighten the dun markings. Cremello and perlinos
have carried the dun dilution gene yet have not exhibited
dun markings. If the horse also carries the gray gene, the
dun markings will fade as the horse’s coat gets progressively
whiter.
The other markings vary from one individual to another. Not all duns will have all of the markings, and nonduns can have some of them. This is an important point,
explains Penedo.
“The primitive marks do not, by themselves, define
dun,” she said. “These marks can be found in horses that
show no dilution of color, as we have observed in many
Iberian horses. Foal coat colors are especially confusing, as
many are born with a dorsal stripe that fades or disappears
over time.”
Not only can markings vary with the horse’s age, but
seasons and condition can also bring changes. They could
be there but simply hard to see. For example, dun markings don’t really show up very clearly in winter coats.
Mystery solved?
“The vast majority of people are confused about dun,
red dun and grulla,” said Lord. “For some reason, dun is
one of the most frequently misidentified colors.”
Castle agrees that dun dilutes can be challenging to
identify.
“Some of the other colors are definitely much easier by
comparison,” she said. “However, with practice and train-
JESSICA HEIN
Horses with a dun dilution, like this grullo, may have
shoulder stripes.
JESSICA HEIN
color hairs mixed in or dividing it into two or more [parallel] stripes.”
Just because your horse has a dorsal stripe doesn’t necessarily mean it is a dun.
JESSICA HEIN
“This basic dun is the one that can be confused with a
buckskin,” said Barbara Kostelnik of Cincinnati, Ohio,
who created dungenes.org to educate horse owners about
dun characteristics. “It will be a tan color with a black
mane and tail, and the markings may be anywhere from
dark red to black in color.”
The dun dilution gene lightens the black base coat to a
grayish color known as grullo (pronounced “grew-yo”) or
grulla (pronounced “grew-ya”). Grulla is the Spanish word
for crane and recalls the bird’s slate-gray color. Keeping
with the name’s Spanish origins, grullo is traditionally used
for stallions and geldings while grulla is used for mares.
Unlike a gray, which when examined closely is a mixture of dark and white hairs, a grulla’s hairs are all the same
grayish color. It can tend toward a tannish shade is some
horses but is usually a “cool” tone tending more to bluish.
Points and markings are black.
Although not recognized as an official APHA color,
brown dun is the result of dun diluting a seal brown base
coat. Lighter brown duns may resemble dark bay duns;
darker brown duns may look like grullos.
“In the past, these would have been hard to identify, but
now that there is a test for seal brown [available through
Pet DNA Services of Arizona], they can be distinguished
from other duns,” said Lord.
Just like a horse can carry multiple coat pattern genes, a
horse can carry multiple dilute genes. For example, add
dun to a palomino—a sorrel or chestnut with a cream
dilution gene—and get a palomino dun or dunalino. Add
dun to a buckskin—a bay base with a cream dilution
gene—and get a buckskin dun or dunskin. And add dun
to a smoky black—a black base with a cream dilution
gene—and get a smoky grullo. These horses are registered
as the color they most closely resemble.
Foals’ coats can make true dun markings hard to identify.
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ing one’s eye to recognize the sometimes subtle differences
between a dun and a non-dun, it gets much easier.”
Some dun mysteries are getting solved the high-tech
way—via genetic testing for dun markers. UC-Davis began
offering a dun zygosity test last year. In cases where it’s not
clear if the horse is a dun or if a breeder wants to know if a
horse is homozygous, genetic testing is certainly useful.
Dun or not dun? Kostelnik gives this bit of advice.
“Never decide whether a particular horse is a dun or
not until you research it thoroughly,” she said. “There is
a great range and variety in dun coloration and markings.”
Breeders and enthusiasts alike are looking forward to
the discovery of the actual mutation that is responsible
for dun dilution and the day they can say with 100 percent certainty, “Case closed. Mystery solved. My horse is
a dun.” n
Special thanks to Dr. Cecilia Penedo, Nancy Castle, Barbara Kostelnik, Julia Lord and Carolyn Shepard for their
invaluable assistance with this article.
or season to season in an individual horse,” he wrote.
When differences between a dun and a non-dun can be
subtle and confusing, even for the experienced breeder,
what’s the best way to tell them apart?
Start with the horse’s pedigree. A dun horse must have
Can a horse have a dark dorsal stripe and not be a
dun? Yes, it’s possible, says Allyson Pennington, APHA a dun parent, unless the parent was mistakenly registered
as a non-dun.
Registrar.
Tracing a horse’s pedigree back to the dun ancestors can
“So many people are misled into thinking they have a
dun or red dun when they do not,” said Pennington. “Peo- be useful. In Quarter Horses, the majority of duns trace
ple see any stripe down the spine and automatically call it back to Yellow Jacket, Blackburn, Joak and Hollywood
a dun and do not understand why we won’t register it with Gold. In Paints, one of the prominent ancestors was Yellow Mount, who has Blackburn and Yellow Jacket in his
that color.”
One common misconception is that a buckskin cannot pedigree.
Next, inspect the horse.
have a dorsal stripe.
“I look for evidence of more than one dun trait to help
“People believe that if the horse does not have a dorsal
it is called buckskin, but if it has a dorsal it is called dun,” me determine if a horse is or is not dun dilute,” said Cassaid Nancy Castle of Paradise, Texas. “Many buckskins do tle. “First, I look for the tone of the color. On bay duns
have a dorsal stripe, which is generally referred to as a and red duns, I look for the body coat to be diluted, but
with some signs of red tones left in the coat. The cream
countershaded dorsal.”
In fact, some dorsal stripes are caused by countershad- gene turns the coat more yellow-gold, while the dun gene
leaves some residual red tones in
ing, also called sootiness or smuttithe coat, so that the tone is more
ness. Countershading modifies the
yellow-tan, sometimes resembody color by adding black hairs,
bling peanut butter or a shade of
usually over the top of the horse
red clay, like the stain of red clay
and down the back, shoulder and
soil. On lighter shades of dun,
croup. In some cases, the counterusually dunskins and dunalinos,
shading is minimal and mimics a
the body coat often has more of
dun’s dorsal stripe. It can also create
a flat peachy-yellow tone.
shading on the shoulder, which
“Then I look for the primitive
could easily be confused with the
markings: their color, intensity of
dun shoulder stripe or shading. But
color and shape and definition.
duns with countershading are
This bay foal exhibits countershading.
It does take some practice,
rarely seen.
though. You have to train your
“Dun pretty much cancels out
‘sooty’ since it dilutes black hair,” said Paint breeder Julia eye to recognize these traits and how they differ from
colors and markings that are similar.”
Lord from North Liberty, Indiana.
If you are registering a foal and are not sure if the youngThe genetics of countershading are still unknown.
According to genetics expert and author D. Phillip Spo- ster is dun or not, it’s helpful to send additional photos
nenberg, “the genetic control of the sooty effect is not sim- with the registration application that clearly show the
ple, nor is it well documented.” He theorizes that more markings you believe qualify the horse as a dun. Because
than one gene may be at work and there is an environ- a dun foal must have at least one dun parent, the APHA
mental link—that horses fed rich diets express sootiness to may require new photos of the parents or even parentage
a greater degree. As a result, “sootiness can vary year to year verification to solve your dun mystery.
COURTESY JULIE YATSKO
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Interview with Cecilia Penedo, PhD
Associate Director, Service and Genomic Research and Development, Veterinary Genetics Laboratory,
University of California, Davis
PHJ: How and when did you and your team at UC-Davis
develop the dun zygosity test?
Dr. Penedo: We began offering the dun zygosity test early
in 2008. The research that led to the development of the
test has been going on for several years. Mapping the dun
gene was the Masters project of my graduate student
Stephanie Bricker. We located dun on one of the horse
chromosomes in 2003. Using all horse genome resources
at the time, the status of the map was the equivalent of
having a street name and a five-block span where the “dun
house” was located.
We have continued to refine the location of the gene and
in the process identified several DNA markers very closely
associated with dun. Continuing with the “street address”
analogy, we know that dun resides in the middle of a block,
but we can only
identify the neighboring houses, that
is, the DNA markers. We studied the
association of these
markers with dun
in many different
breeds and noticed
a common pattern.
Using letters to
designate
the
DNA variants for
the critical markers, the prevalent
pattern becomes
“MMUOQ.” In
homozygous dun
horses, which have
two copies of dun and transmit dun to 100 percent of
foals, the genetic formula is MMUOQ/MMUOQ. In heterozygous dun horses, which have one copy of dun and
transmit dun to 50 percent of foals, it is
MMUOQ/“another pattern.”
PHJ: Can you explain how it works? How accurate is the test?
Dr. Penedo: The basis of the current DNA test is to determine if the horse has the “dun” marker pattern and if it
is present in a single copy (heterozygous) or two copies
(homozygous). There are many different combinations of
DNA variants. To ensure that the correct DNA patterns
(dun and not-dun) are identified, most of the time we test
at least one of the parents to determine which variants are
being transmitted by that parent.
I have to stress, though, that this is what we call an “indirect test.” We are not testing for the actual mutation that
is responsible for dun dilution.
The test is highly accurate (greater than 95 percent) for
the breeds in which it was validated, such as Quarter
Horses, Paints, Appaloosas, Icelandic Horses, Norwegian
Fjords and several of the pony breeds. We have not identified the same pattern in Iberian breeds such as Pure Spanish Horse (PRE), Andalusian and Lusitano, for example.
For this reason, we have restricted the dun zygosity test
only to validated breeds. We continue to investigate the
question about dun in Iberian breeds, among which we
have seen many examples of presence of striping pattern
without dilution of body hair.
PHJ: Can you tell us a bit about current research on the
dun gene?
Dr. Penedo: In recent months, there has been a concerted
effort to find the specific genetic change that causes dun.
We are collaborating with Drs. Leif
Andersson
and
Gabriella Lindgren
from [Dept. of
Medical Biochemistry and Microbiology, Uppsala University] Sweden,
who are also interested in the genetics
of dun gene and
primitive marks,
and with scientists
at The Broad Institute in Boston,
where the horse
genome sequence
work was done.
This collaboration has made it possible to apply the latest
technologies in genome research to find what causes dun.
This research will generate DNA sequence from two homozygous dun horses in the genome region where the gene
is located. These sequences will be compared with those
of not-dun horses. Sequence differences found in these
comparisons will then be investigated for association with
the presence of dun across breeds.
I am very hopeful that we will find the dun mutation
and that a specific test for it will be available in the near future. From a science perspective, the goal is to learn how the
dun mutation affects hair pigmentation to cause the dilution effect, as well as the appearance of the primitive marks.
DUN RESOURCES
duncentralstation.com
dungenes.org
vgl.ucdavis.edu.
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