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y more chestnuts and sorrels.
• Bay mated to bay, black or chestnut/sorrel can pro-
duce bay, chestnut, sorrel, and, rarely, black.
• Black mated to black produces black (or, rarely,
chestnut or sorrel).
• Black mated to bay will usually produce a bay, fairly
commonly produces chestnut or sorrel, and only
rarely produces black.
• Black mated to chestnut will usually produce bay, but
also chestnut or sorrel, and, rarely, black.
Color prediction is never 100 percent accurate. The
best way to maximize the chance of a specific dark
color is to test for the Agouti gene or to mate two par-
ents of that color. Any other approach drastically
decreases the probability of achieving the desired color
in the foal.
Bay Horses
Bay is the second most common horse color. Controlled by the A gene, a
bay horse has a reddish brown body with black points. The A gene creates
these black points by limiting the placement of black on the horse’s coat to
the mane, tail, legs and ears.
The two genetic loci (locations) that control the color of the bay, black
and sorrel horse are the Agouti (A) and Extension (E). The way these loci
interact creates these three
basic body colors.
Agouti controls the distri-
bution of the red and black
areas on horses that can form
black pigment, i.e., blacks,
bays, buckskins, etc.
The dominant A gene
restricts black to the points,
creating a bay. The recessive Agouti gene (a) does not restrict the black, result-
ing in an all-black horse. Therefore, foals with the genotype AA or Aa will be
bay and those with the aa genotype will be black, providing they have the
dominant Extension gene.
The Extension locus interacts with the Agouti to restrict or allow the
expression of black, but unlike the bay gene, it is the recessive form of the
Extension loci that does not allow the color. As a result, a foal inheriting two
copies of the recessive black gene (ee) will be completely sorrel or chestnut,
regardless of what type of Agouti alleles it carries.
In his book Equine Color Genetics, Dr. Philip Sponenberg describes the
Agouti and Extension loci as switches. As a way to remember the effect each
gene has on a horse’s color, one can imagine that the Extension locus deter-
mines if the horse is “chestnut” or “not chestnut.” If the horse is “not chest-
nut,” then the Agouti locus acts as a switch to determine if the horse is “bay”
or “black.”
Understanding how the A and E genes work to create the bay color and affect
the occurrence of sorrel and black will help you to better determine how other
coat colors are created. However, there are still many subtle shades of the bay
coat that cannot fully be explained by the action of the A and E genes.
Bays range in color from dark mahogany bays to blood bays to golden
bays. These bay shades are thought to be under complex, multifactor genet-
ic control. Even environment and nurture can cause a variation in coat color,
with well-fed horses having a deeper, richer coat than those lacking in nutri-
tion. Again, Sponenberg says these variations can be viewed as switches that
trigger either a “dark,” “middle” or “light” shade.
Regardless of the many color variations, bay foals are all born with black
tips on their ears. In addition, most of have black manes and tails;
however, their legs may be light at birth and later
shed to black.
Heterozygous Bay (AaEE)
Mated to Chestnut (Aaee)
Bay
AE aE
Ae
AAeE AaeE
bay bay
ae
aAeE aaeE
bay black
Chestnut
Bay
07CoatColorGenetics 12/14/07 6:52 PM Page 9
10 • APHA Coat Color Genetics Guide
Black and Brown Horses
The black coat color is controlled by the E gene. It is the
expression of the dominant E gene. The homozygous black
horse (EE) has a very rich, black coat that is sometimes called
jet black or coal black. Black horses have an entirely black coat
and their color does not fade out over the flanks in the summer.
Though they are recognized by APHA as a separate color,
brown horses are also genetically controlled by the E gene.
Brown horses have black or nearly black coats with brown or
reddish hairs on the muzzle or flanks.
Black is a popular color with many breeders, but it is
fairly rare. The most reliable way to produce black horses
is by mating two homozygous black horses. Breeding
two heterozygous blacks is the second choice and
breeding a black to any other color horse that carries a
black gene is third. The reason for this is that the E gene
is dominant over the e and the CC
cr
genes that are pres-
ent in palominos. Fortunately, breeders can have their
black or brown horse tested for the recessive e gene so
that they can determine if it is homozygous (EE) or het-
erozygous (Ee).
The problem with breeding black to sorrel is that many
red horses carry the A gene, which turns the black coat to bay.
According to statistics, a heterozygous black and a chestnut
should produce a black foal 50 percent of the time.
However, this is valid only if the chestnut horse (ee) does not
carry the A gene. If the chestnut parent is heterozygous for this
A gene, 50 percent of the blacks will become bays. If it is
homozygous for this gene, 100 percent of the foals will be bay.
Black foals are usually born with a blue-gray hue to their coat
and will typically shed to black as weanlings or yearlings.
Mating Two Heterozygous
Black Parents (Ee)
Black
Ee
E
EE Ee
black black
e
eE ee
black sorrel
Black
Brown
Black
Chestnut
Sorrel
Chestnut and Sorrel Horses
The chestnut horse and the sorrel horse are homozygous reces-
sive ee individuals. Though there is no distinction between the two
colors in the Jockey Club, most breed associations consider the
chestnut and sorrel
different.
Both have a red-
dish body color with
a reddish mane and
tail, which can vary
from dark to light to
flaxen. The differ-
ence is in the
depth of the body color. Chestnuts are a darker red that is
sometimes close to black. Sorrels are a lighter or bright red.
For the purpose of learning to utilize color genetics, this
guide will use the terms interchangeably, because both
colors are created by the homozygous recessive e.
Chestnut and sorrel come in many shades—from
very light sorrel, which can appear close to a palomino
color, to black chestnut. The best way to distinguish a black
chestnut from a black or brown horse is by the copper-colored
highlights on its legs.
Regardless of shade, two chestnut parents will always pro-
duce a chestnut foal, making it the easiest color to breed for. Mating
of two heterozygous blacks (Ee) will produce chestnuts 25 percent
of the time.
In addition, sorrel is a valuable color when trying to breed col-
ors based upon the red color, like palomino, red roan and red dun.
Sorrels that have two copies of the recessive Agouti locus (aa) are
valuable to breeders raising black horses because they will not turn
black to bay. For the same reason, it will never produce a bay roan
when bred to a blue roan. A test is available to determine the genet-
ic A code of sorrel individuals.
Sorrel and chestnut foals are born with reddish coats that may
lighten or darken when they shed.
Mating Heterozygous Black (Ee)
Mated to Sorrel (ee)
Black
Ee
e
eE ee
black sorrel
e
eE ee
black sorrel
Sorrel
07CoatColorGenetics 12/14/07 6:52 PM Page 10
Cremello and Perlino Horses
A horse that receives two copies (C
cr
C
cr
) of the cremello gene
has a cream-colored coat with pink skin and blue eyes. When
two pairs of C
cr
occur in a horse with a chestnut base color, the
resulting body coat color is called cremello. When two C
cr
genes
occur in a horse with a bay base color, it creates a color known
as perlino.
As foals, a perlino and cremello look almost identical, both
with pink skin, blue eyes and a washed-out coat color. White
markings on the face and legs are barely visible next to the slight-
ly yellow coat. Sometimes, these foals are mistakenly referred to
as albinos.
Many breeders will not mate two palominos because of the
chance of raising a cremello. Using the Punnett Square, you can
determine that 25 percent of the foals from a palomino-to-
palomino mating will receive two copies of the CC
cr
gene.
Breeding palominos to buckskins, or buckskins to buckskins,
results in a 25 percent chance of raising a perlino. The cremello
gene creates both the buckskin and the palomino—the only dif-
ference is the base color upon which it is acting. Both palominos
and buckskins result from the heterozygous (C
cr
C) cremello gene
combination. However, the buckskin’s base coat color is bay, and
the palomino’s base coat color is sorrel or chestnut.
The benefit derived from cremello and perlino breeding stock
is that Paint breeders can produce palominos and buckskins 100
percent of the time. A cremello bred to a sorrel will always pro-
duce a palomino and a perlino bred to a bay or sorrel will always
produce either a palomino or buckskin.
APHA Coat Color Genetics Guide • 11
Champagne and Cremello Genes
Scientists have identified three genes that create the
coat colors palomino, buckskin and dun. Of these genes,
the champagne and the dun (see page 13) gene, express
themselves according to the rules of similar dominance.
As a result, they dilute the horse’s base color only when
the dominant expression of the gene is present. Whether
the horse has two copies of the dominant gene or only
one, the coat color looks the same.
Palomino/Buckskin (C
cr
C) Mated to
Palomino/Buckskin (C
cr
C)
Palomino/
Buckskin
C
cr
C
C
cr
C
cr
C
cr
C
cr
C
homozygous dilution
dilution
(cremello/perlino)
C
CC
cr
CC
dilution no dilution
Palomino/
Buckskin
The Champagne Gene
The champagne (Ch) gene is not as commonly recognized
as some other genes for coat colors. The dominant form of
the champagne gene (Ch
C
) gives horses an iridescent glow
to their coats. Their eyes are amber and their skin is pump-
kin-colored or a pinkish-gray. Researchers have identified
the gene in the Tennessee Walking Horse, the Rocky
Mountain Horse, the Quarter Horse and the Paint Horse.
In his book Equine Color Genetics, Sponenberg reports
that the champagne gene dilutes a chestnut coat to
golden with a flaxen mane and tail (golden cham-
pagne). Its action on black turns the coat to classic
champagne, the bay coat becomes tan with a dilute
mane and tail, known as amber champagne, while the
action on brown becomes sable champagne.
A champagne-dilute foal is often born dark-colored and
will lighten to champagne when it sheds for the first time.
For this reason, it is likely that many champagne horses
have been registered as palomino, buckskin and sorrel.
Owners of champagne horses who want their horse’s
color recognized can contact the International Cham-
pagne Horse Registry, which is the official registry for
the color. To find out more, log on to their Web site at
ichregistry.com.
The Cremello Gene
The cremello gene produces the palomino and buckskin
color, but unlike the other dilution genes, it follows the rule
of incomplete dominance. As a result, the gene can
express itself in three ways, depending on the combina-
tion in which it occurs.
One copy of the dominant (C
cr
) gene turns the horse’s
coat to either palomino or buckskin. Two copies of the C
cr
gene dilute the coat to perlino or cremello.
The cremello gene is not expressed when it occurs in
the homozygous recessive (CC) form. The same rule
applies to the champagne and dun genes.
Perlino
Cremello
07CoatColorGenetics 12/14/07 6:52 PM Page 11
12 • APHA Coat Color Genetics Guide
The palomino horse is a chestnut
horse (ee) with one C
cr
gene. The
Palomino Horse Breeders of America, a
color breed registry for palominos,
describes the color as that of a U.S. 14
karat gold coin, with variations from light
to dark. However, the body coats can
vary from a smoky gray to creamy yel-
low. Palominos may have manes the
color of their bodies or they can be
white, silver or mixed with sorrel. Their
skin is usually gray, black, brown or mot-
tled, without underlying pink skin or
spots except on the face or legs.
A palomino foal’s true color may not
be evident at birth. Some will have yel-
lowish bodies and white manes and
tails, making them easy to identify. But
some are born with a sorrel coloring.
These foals tend to have an orange or
pink tint to their coats, and their manes
and tails may be slightly red. As wean-
lings or yearlings, these foals will shed
their sorrel coat for their true palomino
color.
Fortunately, a breeder in doubt has
one sign on which they can rely. The
color of the foal’s eyelashes provides a
good clue to the foal’s eventual coat
color. Palominos born with sorrel coats
usually have light, golden eyelashes.
For breeders who cannot utilize
cremellos or perlinos in their breeding
programs, crossing a sorrel with a
palomino has the best odds of produc-
ing a palomino—a 50 percent chance.
A palomino mated with a black horse
may produce a palomino or a black foal,
depending on which black gene combi-
nation it receives. The black gene (E)
masks the expression of the C
cr
gene.
This is why a black horse crossed on a
palomino is the third-best way to pro-
duce a black foal. Also, a heterozygous
black (Ee) horse with a palomino parent
can produce a palomino if it passes on a
recessive e and a C
cr
. If that horse’s
mate also has the recessive e gene, the
resulting foal can receive an eeC
cr
C
combination, making it a palomino.
A variety of coat colors can result
when breeding a palomino to a het-
erozygous bay. These foals have a 25
percent chance of becoming buckskin,
palomino, bay or sorrel.
Of course, the Punnett Square only esti-
mates gene action, because there are
other factors that change breeding per-
centages. Its predictions work over a large
population, but any horse can deviate.
Palomino Horses
Palomino (eeaaC
cr
C) Mated to
Heterzygous Bay (EeAaCC)
Palomino
eaC
cr
eaC
EAC
EeAaCC
cr
EeAaCC
buckskin bay
eaC
eeaaCC
cr
eeaaCC
palomino sorrel
Bay
Buckskin Horses
Buckskins are canvas-colored with black tips
on their ears and black legs, like bays. Their body
color ranges from purple to sand to cream.
Buckskin is produced by the dominant cremel-
lo gene (C
cr
) acting on a bay base color.
Buckskin foals are fairly easy to identify
at birth. Born with light bodies and black
ear tips, their legs may be dark but usu-
ally appear light and then shed to dark.
Markings can be tricky to detect on a buckskin Paint
when the Paint gene colors the legs white. Hoof color
can sometimes be helpful, as a buckskin Paint should
have dark hooves.
For breeders who cannot utilize cremellos or perli-
nos in their breeding programs, crossing a bay with a
buckskin is the second-best way of producing the
color, with a 50 percent chance.
A 50 percent chance can
also be obtained by breeding
a palomino to a bay that
is homozygous for the black
gene and the bay gene (EEAA).
This cross also produces 50
percent bays.
Palomino (eeaaC
cr
C) Mated to
Homozygous Bay (EEAACC)
Palomino
eaC
cr
eaC
EAC
EeAaCC
cr
EeAaCC
buckskin bay
EAC
EeAaCC
cr
EeAaCC
buckskin bay
Bay
07CoatColorGenetics 12/14/07 6:52 PM Page 12
The coat color categorized as dun has one
of the broadest ranges of colors and mark-
ings. For APHA purposes, horses with a dun
coat are categorized as either dun or red dun.
Dun is the result of the dominant dun
gene (Dn
+
) working on a bay base coat. The
effect is to lighten the body to a tan or gold-
en yellow color. A red dun occurs when the
Dn
+
gene expresses itself on a chestnut or
sorrel coat. Red duns have a light red,
orangish or sometimes apricot coat color.
All duns, regardless of body color, have one
thing in common—primitive markings. There
are basically four types of primitive markings:
zebra stripes, dorsal stripe (lineback), withers
stripe and cobwebbing. Zebra stripes are bars
on the side of the hocks and above or below
the knees. A dorsal stripe is a dark stripe down
the back. A withers stripe is a stripe across the
withers, and cobwebbing is expressed by con-
centric darker rings on the forehead.
Not all duns express each of these traits,
but some do. They can have any combina-
tion of these markings.
Researchers believe the dun gene lightens
the body, leaving the horse’s dark points unaf-
fected and leaving the head darker than the
body. The mane and tail are also often darker.
The lineback is the most common dun
feature. The darker color of the lineback
often continues into the mane
and tail, where the gene action
darkens the center of the hair
and leaves the edges lighter.
Dark-colored horses such as
black, bay and chestnut may have
a back stripe without a lightened
body color. Similarly, foals are
sometimes born with a lineback
that disappears when they shed. However,
scientists believe these back stripes are not
caused by the dun gene. These back stripes
are referred to as “counter-shading”.
Dark edging on the ear is another com-
mon dun characteristic, but because this
characteristic is common in other colors, it is
probably not related to the dun gene (Dn
+
).
Following the rules of similar dominance,
the recessive dun gene (Dn
nd
) does not affect
the outcome of a horse’s color. Scientists still
do not know if the dun gene acts alone, or if
there are other genes that work to create the
many different dun characteristics.
Dun Horses
APHA Coat Color Genetics Guide • 13
Heterozygous Dun (eeaaCCD
n+
Dn
nd
) Mated
to Homozygous Bay (EEAACCDn
nd
Dn
nd
)
Dun
eaCDn
+
eaCDn
nd
EACDn
nd
EeAaCCDn
nd
Dn
+
EeAaCCDn
nd
Dn
nd
dun bay
EACDn
nd
EeAaCCDn
nd
Dn
+
EeAaCCDn
nd
Dn
nd
dun bay
Bay
Primitive Markings
Leg Barring:
Horizontal stripes of
varying widths appearing
across the hocks, gaskins,
forearms or knees.
Dorsal Stripe:
Darker band of color run-
ning along the backbone
from the withers to/into the
base of the tail.
Shoulder/Traverse Stripes:
Neck and shoulder
shadowing appearing as
dark areas through the
neck or withers.
Grullo Horses
Grullo is one of the rarest expressions of
the dun gene because it results from the
action of the dun gene on a black base
coat. It was once believed that grullos
resulted from crossing palominos with black
horses, but genetic research has since
proved that theory incorrect.
The grullo coat varies from beige to bluish-
gray to slate blue. They usually have dark or
black heads and black points, mane and tail.
As the dun gene acts through similar
dominance (see page 14), grullo is created
by a single copy of the Dn+ gene. However,
homozygous duns (Dn+Dn+) do exist and
will pass on a dominant dun gene to each
of their offspring, resulting in 100 percent
duns and grullos.
Another interesting result
of the dun gene occurs
when a horse also carries
the dominant form of the
cremello (Ccr) gene, which
creates cremellos, perlinos,
palominos and buckskins.
A black horse that receives
the Dn+ gene and is
also heterozygous for the
cremello gene (CCcr) will result in a paler
grullo. On a bay base coat, the primitive
marks may remain but the body becomes
more yellow, like a buckskin. On a sorrel
coat, the primitive marks may be lost alto-
gether and the body becomes the color of
a palomino. For this reason, the colors of
some horses may
have been incorrect-
ly registered, which
could explain why
breeders once
believed a palomino
could produce a
grullo. In actuality, the
palomino was a
palomino-
colored dun without the dorsal stripe.
Scientists believe that when CCcr x Dn+
occurs, the gene that has the most extreme
expression of the base coat color is the one
that is dominantly expressed. For instance,
a chestnut coat would be lightened to
palomino because palomino is a more
extreme change than is red dun.
Heterozygous Black (EeaaCCDn
nd
Dn
nd
) Mated
to Heterozygous Red Dun (eeaaCCDn
+
Dn
nd
)
Black
EaCDn
nd
eaCDn
nd
eaCDn
+
eEaaCCDn
+
Dn
nd
eeaaCCDn
+
Dn
nd
grullo red dun
eaCDn
nd
eEaaCCDn
nd
Dn
nd
eeaaCCDn
nd
Dn
nd
black sorrel
Red
Dun
07CoatColorGenetics 12/14/07 6:52 PM Page 13
14 • APHA Coat Color Genetics Guide
The Difference Between Roan,
Gray and White
Three of the most easily confused
colors are roan, gray and white.
Though all result from white being
added to the horse’s base coat, each
has a unique way in which it occurs.
The roan gene (RnRn) covers specific
parts of the body with a light coating of
white hairs that are evenly mixed within
the base coat. The gray gene (G) begins
as a light sprinkle of white over the entire
coat. Each year, more white hairs are
added to the coat until it is completely
gray or white. The white gene (W) com-
pletely covers the body with an even,
white coat before the foal is born.
By becoming familiar with the spe-
cific characteristics unique to each
color, a breeder can reliably identify
one from the other. Because these
three genes add white to the basic coat
color of the horse, the horse’s other
gene combinations of E, A, C
cr
, Dn
nd
,
Ch, etc., still determine the color that is
being covered by the coating of white.
Roans are often confused with gray horses
because both are characterized by having
white in their hair coats. However, the differ-
ence between the action of the roan gene and
the gray gene is evident once you understand
the specific effec