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The Magical Mystery of "A
Gypsy Cob"
Image Copyright Gerald R Wheeler
Detailed Colour Coat
Info
Colour
coat calculator:
CLICK HERE
Red Factor
The Extension gene (red factor) has two alternative states (alleles). The
dominant allele E produces black pigment in the coat. The recessive allele e
produces red pigment. Red horses (chestnuts, sorrels, palominos and red
duns, to name a few) are homozygous, that is they have two alleles, for the
recessive red allele ee. Black pigmented horses (black, bay, brown, buckskin
and grullo, to name a few) have at least one E allele. They can be
homozygous EE or heterozygous Ee. A horse that is homozygous EE will not
produce red offspring, regardless of the colour of the mate.
The DNA diagnostic test for red factor can be used to identify those black
horses for which neither pedigree nor breeding records is informative for
identifying carriers of the recessive red factor. Since red is inherited as
a recessive trait, it is relatively easy to start up a breeding program that
will produce only red horses. It has been more difficult to initiate a black
breeding program as black Ee horses can produce red foals. Prior to the
development of this test, only pedigree or breeding records, not phenotype,
could provide information about whether black horses are EE or Ee.
Red Factor results are reported as:-
|
e |
Only
the red factor detected. The horse can be assumed to be homozygous
for red (ee). The basic color is sorrel or chestnut, but depending
on genes at other color loci, the horse could be palomino, red dun,
gray, cremello, white or any of these colors with the white hair
patterns tobiano, overo, roan or appaloosa. |
|
E/e |
Both
black and red factors detected. The horse can be assumed to be
heterozygous for the red factor (Ee). It can transmit either E or e
to its offspring. The basic color of the horse will be black, bay or
brown, but depending on genes at other color loci, the horse may be
buckskin, zebra dun, grullo, perlino, gray, white or any of these
colors with the white hair patterns tobiano, overo, roan or
appaloosa. |
|
E |
No
red factor detected. The horse can be assumed to be homozygous for
black pigment (EE). It cannot have red foals, regardless of the
color of the mate. The basic color of the horse will be black, bay
or brown, but depending on genes at other color loci, the horse may
be buckskin, zebra dun, grullo, perlino, gray, white or any of these
colors with the white hair patterns tobiano, overo, roan or
appaloosa. |
Agouti (bay/black)
Agouti results
are reported as:
|
A/A or A/a |
Black
pigment distributed in point pattern. The basic color of the horse
will be bay or brown in the absence of other modifying genes. A has
no effect on red pigment (ee). |
|
a |
Only
recessive allele detected. Black pigment distributed uniformly. The
basic color of the horse will be black in the absence of other
modifying genes. |
Champagne
Champagne is a dominant gene that dilutes hair pigment from black to brown
and red to gold. Champagne on a chestnut background (Gold) produces a gold
body color and often a flaxen mane and tail that can be mistaken for
palomino. Champagne on a bay background (Amber) produces a tan body color
with brown points. Champagne on a black background (Classic) produces a
darker tan body with brown points. The skin of Champagne-diluted horses is
pinkish/lavender toned and becomes speckled with age; the speckling is
particularly noticeable around the eye, muzzle, under the tail, udder and
sheath. The eye color is blue-green at birth and darkens to amber as the
horse ages. Champagne is inherited independently of other coat color genes
and thus this dilution can occur in combination with any of the other genes
that modify the base colors. Champagne dilution is found in Tennessee
Walking Horses, Missouri Fox Trotters, Quarter Horses and related breeds,
Miniature Horses and Spanish Mustangs, among others. The increasing
popularity of this color is making it more common in these breeds. A
mutation in the
Solute Carrier 36 family A1 (SLC36A1)
gene was found to be associated with the Champagne dilution.
The Veterinary Genetics Laboratory offers a test for Champagne that detects
the mutation in
SLC36A1
gene.
Champagne results are reported as:-
|
N/N |
No
evidence of the altered sequence detected |
|
N/Ch |
One
copy of the altered sequence detected. Chestnut color (red) is
diluted to gold, bay to tan with brown points and balck to darker
tan with brown points. |
|
Ch/Ch |
Two
copies of the altered sequence detected. All offspring are expected
to be Champagne dilute. |
Cream
The Cream dilution gene is responsible for the palomino, buckskin, smoky
black, cremello, perlino and smoky cream coat colors. There are two alleles:
CCr and C. CCr is semi-dominant and dilutes red to yellow in single dose
(palominos, buckskins, smoky blacks) and to pale cream in double dose (cremellos,
perlinos, smoky cream). Cream dilution can have a very subtle effect on
black pigment. C is recessive and does not dilute the base colour.
Cream dilution
results are reported as:
|
N/N |
Non-dilute. Basic colors are chestnut, bay, black or brown in the
absence of other modifying genes. |
|
N/Cr |
Heterozygous, dilute, one copy of the Cream CCr allele. Chestnut is
diluted to palomino; bay is diluted to buckskin and black is diluted
to smoky black. These colors can be further modified by the actions
of other genes |
|
Cr/Cr |
Double dilute (two copies of the CCr allele). Chestnut is diluted to
cremello; bay is diluted to perlino and black is diluted to smoky
cream. |
Note: The test offered by VGL is specific for a mutation in exon 2 of the
MATP gene that is associated with Cream Dilution. Other dilution genes or
mutations that may produce coat colors that phenotypically resemble cream
will not be detected by the test.
Dun Zygosity Information:
Gray:
The Gray gene causes progressive depigmentation of the hair, often resulting
in a coat color that is almost completely white by the age of 6-8 years.
Horses that inherit progressive Gray can be born any color, then begin
gradually to show white hairs mixed with the colored throughout the body.
Usually the first signs of gray hair can be found on the head, particularly
around the eyes. Gray is dominant, therefore a single copy of this gene will
cause a horse to turn gray. If a horse has two copies of Gray, all offspring
of this horse will be gray. Research indicates that horses with one copy of
Gray often retain some of the original pigment while homozygotes tend to
progress to almost completely white. Gray is found in many breeds and is
the predominant color of the Lippizaner breed.
Gray horses have a high incidence of dermal melanomas that are commonly seen
around the tail and head. Over 70% of Gray horses older than 15 years will
develop melanoma. Gray homozygotes are more likely to develop melanoma than
heterozygotes. Gray horses that are homozygous for non-agouti (“aa”
genotype at the Agouti locus) also have a higher risk for melanoma. Many
Gray horses show depigmentation of the skin around the eyes, mouth and anus
but there are no health risks associated with this condition.
at Uppsala University in Sweden discovered that a 4.6 kilobases duplication
in intron 6 of gene
syntaxin 17
(STX17)
produces progressive graying in horses.
Grey results
are reported as:
|
N/N |
No
copies of the gray gene. Horse will not turn gray. |
|
N/G |
One
copy of the gray gene. Horse will turn gray and approximately 50%
of offspring will be gray. |
|
G/G |
Two
copies of the gray gene. Horse will turn gray and all offspring
will be gray. |
PEARL:
Horses have four common coat color dilution genes with defined phenotypes:
Cream, Dun, Silver and Champagne. Two rare dilution phenotypes have been
recognized in Quarter Horses and Spanish horse breeds such as Andalusians
and Lusitanos. In Spanish horses, this dilution is known as Pearl. In
Quarter Horses and Paints, it has been commonly known as "Barlink Factor".
The two dilutions have been assumed to be different. Research at the
Veterinary Genetics Laboratory (VGL) on the Quarter Horses/Paints identified
a mutation associated with the "Barlink Factor" dilution. Further research
has shown that the same mutation is present in Spanish horses with the Pearl
phenotype. The presence of this mutation in Quarter Horses and Paints likely
reflects the Spanish horse ancestry of these modern breeds. To recognize
that this mutation probably originated in Spanish horses, it is appropriate
to name it Pearl.
Pearl behaves as a recessive gene with respect to the hair color. One dose
of the mutation does not change the coat color of black, bay or chestnut
horses. Two doses on a chestnut background produce a pale, uniform apricot
color of body hair, mane and tail. Skin coloration is also pale. Pearl is
known to interact with Cream dilution to produce pseudo-double Cream dilute
phenotypes including pale skin and blue/green eyes.
Pearl dilution results are reported as:
|
N/N |
No
evidence of altered sequence detected. |
|
N/Prl |
One
copy of the altered sequence detected. If Cream dilution is also
present, a pseudo-double Cream phenotype will result. |
|
Prl/Prl |
Two
copies of the altered sequence detected. On a chestnut base color, a
uniform apricot color of body hair, mane and tail will result. |
SILVER:
The horse Silver dilution gene dilutes black pigment but has no effect on
red pigment. The mane and tail are lightened to flaxen or silver gray, and
may darken on some horses as they age. A solid black horse with this gene
will be chocolate colored with a lightened mane and tail. A bay horse will
have the black pigment on the lower legs, mane and tail lightened. Sometimes
bay horses with Silver dilution can be mistaken for chestnuts with a flaxen
mane and tail. Silver dilution is inherited as a dominant trait. It is known
to occur in Rocky Mountain horses and related breeds, Shetland ponies,
Icelandic and Morgan horses.
The gene responsible for Silver dilution has been recently identified as
PMEL17
by researchers in Sweden. Two single nucleotide substitutions have been
found to be associated with the dilution, one in intron 9 --
A
(normal) to
T
(silver) -- and the other in exon 11 --
C
(normal) to
T
(silver). VGL's test for Silver dilution assays both sites.
Silver dilution results are reported as:-
|
N/N |
No
evidence of altered sequence detected. |
|
N/Z |
One
copy of the altered sequence detected. Black-based horses will be
chocolate with flaxen mane and tail. Bay-based horses will have
pigment on lower legs lightened and flaxen mane and tail. No effect
on chestnut color. |
|
Z/Z |
Two
copies of altered sequence detected. Black-based horses will be
chocolate with flaxen mane and tail. Bay-based horses will have
pigment on lower legs lightened and flaxen mane and tail. No effect
on chestnut color. |
Lethal White Overo:
Horse breeding programs specializing in overo have particular challenges
compared with programs for other white patterns such as tobiano. Not only is
there the possibility of producing a solid dark foal without the overo
pattern but there is also the risk of producing an all-white foal that dies
of complications from intestinal tract abnormalities (ileocolonic
aganglionosis). As far as we are aware, overo horses themselves have no
specific health risks. While breeding evidence shows that some overos are
heterozygous for a gene that is lethal in the homozygous condition, it has
not been easy to identify which horses have the overo gene that is
associated with the lethal white foal syndrome. Occasionally even
solid-colored horses without obvious body spotting patterns have been
reported to produce lethal white foals. Clearly the spotting pattern
classified as overo is phenotypically and genetically heterogeneous.
Breeders can test horses for this mutation to avoid producing lethal white
foals and to identify new pedigree sources of the overo gene that may be
useful in their breeding programs. The gene appears to be associated with
horses often characterized as "frame-overos" in Paints and Thoroughbreds,
but is also present in some tobiano/overos, some solid-colored (breeding
stock Paint) offspring from overo matings, some tobianos and Quarter Horses
without obvious evidence of the overo pattern. The gene has also been
identified in an overo Miniature horse.
Using the letter "O" to symbolize the DNA sequence of the lethal white (LW)
overo gene and "N" for the sequence of the non-overo, then the lethal white
foals can be symbolized as OO, their overo parents as NO and non-overos as
NN.
Breeding predictions between LW overos (NO x NO):
| |
N |
O |
|
N |
25%
NN solid |
25%
NO overo |
|
O |
25%
NO overo |
25%
OO lethal |
Breeding predictions between LW overo and solid (NO x NN): No possibility of
lethal white foals.
| |
N |
O |
|
N |
50%
NN solid |
50%
NO overo |
We know of no other mutations that are associated with lethal white overo
horses. However, owners requesting the diagnostic test should understand
that there is the rare possibility that two NN horses could have a lethal
white foal due if both the sire and dam carry a mutation at a site other
than the one detected by this test.
Sabino 1:
Sabino is a generic description for a group of similar white spotting
patterns. The sabino pattern is described as irregular spotting usually on
the legs, belly and face, often with extensive roaning. A mutation has
recently been discovered that produces one type of sabino pattern. It has
been named Sabino1 as it is not present in all sabino-patterned horses. More
mutations will probably be identified that account for other sabino
patterns.
Sabino1 is inherited as an autosomal dominant mutation. One copy of the
Sabino1 gene is expected to produce horses with two or more white legs or
feet -- often with white running up the anterior part of the leg, an
extensive blaze, spotting on the midsection, with jagged or roaned margins
to the pattern. Horses with 2 copies of the Sabino1 gene, are at least 90%
white and are referred to as Sabino-white.
Sabino1 is most commonly found in Tennessee Walking Horses. Other breeds in
which this mutation has been found include: American Miniature Horses,
American Paint Horses, Aztecas, Missouri Foxtrotters, Shetland Ponies,
Spanish Mustangs and Pony of the Americas. Other breeds of horses that are
known to have sabino patterns, such as Clydesdales and Arabians, have so far
tested negative for the Sabino1 mutation, although the number of animals
tested is low.
Sabino 1 results are reported as:
|
N/N |
No
evidence of altered sequence detected. |
|
N/SB1 |
One
copy of the Sabino1 gene detected. Horse typically may have 2 or
more white legs, blaze, spots or roaning in the midsection and
jagged margins around white areas. |
|
SB1/SB1 |
Two
copies of the Sabino1 gene detected. Complete or nearly complete
white phenotype expected. |
Tobiano:
The tobiano white spotting pattern is a trait controlled by a dominant gene.
The pattern is clearly marked and characterized by white across the spine
that extends downward between the ears and tail. The skin underlying the
white spots is pink and under the colored areas it is black. The eyes are
usually brown, but one or both may be blue or partially blue. The head is
dark, with white markings like those of a solid colored horse. Usually, all
four legs are white below the hocks and knees. The spots are generally
regular and distinct as ovals or round patterns. The tail can be two
colors—a characteristic seldom seen in horses that are not tobiano. A
tobiano can be predominantly dark or white.
The tobiano gene has two alternative states (alleles). The dominant allele,
TO, produces the tobiano pattern and the recessive allele, to, is non-tobiano
(called N by VGL). A horse that is homozygous for tobiano, symbolized as
TO/TO, will always produce offspring that are tobiano regardless of the
mate. For breeders interested in producing tobiano foals, it is obvious that
a horse that is homozygous for tobiano is desirable in a breeding program.
As most owners do not want to wait for progeny information from a very young
horse and secondary spotting is not absolutely associated with tobiano
homozygosity, a test is available that can help predict the likelihood that
a horse is homozygous for Tobiano.
Unlike other white spotting patterns caused by specific changes in DNA
sequence of the genes, Tobiano is associated with a large chromosome
inversion that affects the function of the gene KIT. The inversion
associated with the Tobiano pattern was identified by researchers at the
University of Kentucky. VGL now offers a direct test for Tobiano which is
available along with our other coat color and pattern diagnostic assays.
Tobiano results are reported as:
|
N/N |
No
evidence of altered sequence detected. Horse is not Tobiano |
|
N/TO |
One
copy of altered sequence. Approximately 50% of the offspring will
inherit Tobiano |
|
TO/TO |
Two
copies of altered sequence. Horse is Homozygous for Tobiano. All
offspring will inherit Tobiano |
Equine Coat Colour Info cont
...
Palomino:
chestnut horse that has one cream
dilution gene that turns the horse to a golden, yellow, or
tan shade with a flaxen or white mane and tail. Often cited
as being a color "within three shades of a newly minted gold
coin," palominos range in shades from extremely light,
almost cremello, to deep chocolate, but always with a white
or flaxen mane and tail.
Pearl:
Also called the "barlink factor," A
dilution gene
that when
homozygous,
lightens red coats to a uniform apricot-like color, often
also resulting in horses with blue eyes. When combined with
cream dilution, may produce horses that appear to be
cremello or perlino.
Perlino:
similar to a cremello, but is genetically a bay base coat
with two dilute genes. Eyes are blue. Mane, tail and points
are not black, but are usually darker than the body coat,
generally a reddish or rust color, not to be confused with a
red dun.
Pinto:
a multi-colored horse with large patches of brown, white,
and/or black and white. Variations include:
Piebald:
a black and white spotting pattern (term more commonly used
in the UK than the USA)
Skewbald:
a spotting pattern of white and any other color other than
black, or a spotting pattern of white and two other colors,
which may include black. (term more commonly used in the UK
than the USA).
Overo:
Describes a group of spotting patterns genetically distinct
from one another, characterized by sharp, irregular markings
with a horizontal orientation, usually more dark than white.
In some cases, the face is usually white, often with blue
eyes. The white rarely crosses the back, and the lower legs
are normally dark. Variations include "Frame
Overo" and "Splashed
white." Sometimes
Sabino
is also classified in the overo family.
Sabino:
Often confused with roan or
rabicano,
a slight spotting pattern characterized by high white on
legs, belly spots, white markings on the face extending past
the eyes and/or patches of roaning patterns standing alone
or on the edges of white markings
Tobiano:
Spotting pattern characterized by rounded markings with
white legs and white across the back between the withers and
the dock of the tail, usually arranged in a roughly vertical
pattern and more white than dark, with the head usually dark
and with markings like that of a normal horse. i.e. star,
snip, strip, or blaze.
Tovero:
spotting pattern that is a mix of tobiano and overo
coloration, such as blue eyes on a dark head. May also refer
to horses with Tobiano coloring that carry a recessive overo
gene.
Paint:
pinto horses with known Quarter Horse and/or Thoroughbred
bloodlines. This is a separate breed of horse.
Rabicano:
A roan-like effect that is caused by a genetic modifier that
creates a mealy, splotchy, or roaning pattern on only part
of the body, usually limited to the underside, flanks, legs,
and tail head areas. Unlike a true roan, much of the body
will not have white hairs intermingled with solid ones, nor
are the legs or head significantly darker than the rest of
the horse.
Roan:
a color pattern that causes white hairs to be evenly
intermixed within the horse's body color. Roans are
distinguishable from greys because roans typically do not
change color in their lifetimes, unlike gray that gradually
gets lighter as a horse ages. Roans also have heads that are
either solid-colored or much darker than their body hair,
and do not lighten. Variations of roan include:
Red Roan: A chestnut base coat with
roaning pattern with the mane and tail being the same red as
the body. Red roans are also commonly referred to as a
Strawberry Roan, and the term Red Roan is occasionally is
used to describe a Bay Roan
Bay Roan: A Bay base coat with roaning
pattern (the mane and tail of the Bay Roan will be Black).
Bay roans are sometimes also called Red Roans
Blue Roan: A black with roaning pattern,
not to be confused with a gray or a blue dun/grullo. A roan
tends to have a darker head, while grays not only lighten
with age, but their heads tend to lighten before the rest of
their bodies. A blue roan has mixed-color hairs, a blue dun
will usually be a solid color and have dun striping.
Silver
dapple:
Caused by a dilution gene that only acts upon black hair
pigment, it lightens black body hair to a chocolate brown
and the mane and tail to silver. The gene may be carried but
will not be visible on horses with a red base coat. Silver
dapple horses may also be called Chocolate, Flax, or Taffy.
Smoky black:
Horse visually appears to be either a black with a mildly
bleached-out coat or a dull dark bay, but is actually has a
black base coat and one copy of the
cream gene.
Smoky Cream:
Virtually indistinguishable from a cremello or perlino
without DNA testing, a horse with a black base coat and two
copies of the cream gene.
White :
One of the rarest colors, a white
horse has white hair and fully or largely unpigmented (pink)
skin. These horses are born white, with blue or brown eyes,
and remain white for life. A truly white horse occurs one of
two ways: either by inheriting one copy of a "dominant
white" ("W") gene, of which several have been identified, or
is a particular type of
sabino
that is
homozygous
for the "SB-1" gene. However, the vast majority of "white"
horses are actually
grays
with a fully white hair coat. As noted above, there are no
true albinos in the horse world.
Reference:
http://en.wikipedia.org/wiki/Equine_coat_color
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Equine Coat Colour Info
BAY:
Body color
ranges from a light reddish-brown to very dark brown with
"black points." (Points refer to the mane, tail, and lower
legs). The main color variations are:
Dark bay: very dark red or brown hair, difficult to
distinguish from
seal brown.
Sometimes also called "black bay," "mahogany bay," or
"brown."
Blood bay: bright red hair, the shade variation often
considered simply "bay."
Light bay: lighter than a blood bay, but hairs still clearly
more red than gold
Brown:
The word "brown" is used by some
breed
registries
to describe dark bays. Informally, it is applied to many
distinct coat colors. Most often, horses described by casual
observers as "brown" are actually bay or chestnut. Absent
DNA testing, chestnut and bay can be distinguished from one
another by looking at the mane, tail and legs for the
presence of black points. However, true
seal brown
is genetically distinct from both bay and chestnut.
CHESTNUT:
A reddish body color with no
black. Mane and tail are the same shade or
lighter than the body coat. The main color
variations are:
Liver
chestnut: very dark
brown coat. Sometimes a liver chestnut is
also simply called "brown."
Sorrel:
Reddish-tan to red coat, about the color of
a new penny. The most common shade of
chestnut.
Blond or
light chestnut:
seldom-used term for lighter tan coat with
pale mane and tail that is not quite a dun.
GRAY:
A horse with black skin but
white or mixed dark and white hairs. Gray
horses can be born any color, lighten as
they age, and eventually most will have
either a completely white or "fleabitten"
hair coat. Most "white" horses are actually
grays with a fully white hair coat. A gray
horse is distinguished from a white horse by
dark skin, particularly noticeable around
the eyes, muzzle, flanks, and other areas of
thin or no hair. Variations of gray a horse
may exhibit over its lifetime include:
Salt and Pepper or "steel"
gray:
Usually a younger horse, an
animal with white and dark
hairs evenly intermixed over
most of the body.
Dapple gray:
a dark-colored horse with
lighter rings of graying
hairs, called dapples,
scattered throughout.
Fleabitten gray:
an otherwise fully
white-haired horse that
develops red hairs flecked
throughout the coat.
Rose gray:
a gray horse with a reddish
or pinkish tinge to its
coat. This color occurs with
a horse born bay or chestnut
while the young horse is
"graying out."
Albino:
There are no
"albinos",
defined as
animals with
a white coat
with pink
skin and
pink eyes,
in the horse
world. The
genetic
factors that
create
albinism,
for reasons
not yet
fully
understood,
are lethal
in horses.
If a foal is
conceived as
a
homozygous
"dominant
white," the
mare
will either
abort the
foal or
reabsorb the
embryo. A
foal with
Lethal white
syndrome
dies shortly
after birth.
However,
some horses
are born
with white
hair, blue
or brown
eyes, and
unpigmented
skin that
are healthy.
See "white,"
below
for
description
of a truly
white
horse.
Black:
Black is
relatively
uncommon,
though not
"rare."
There are
two types of
black,
fading black
and
non-fading
black. Most
black horses
will fade to
a brownish
color if the
horse is
exposed to
sunlight on
a regular
basis.
Non-fading
black is a
blue-black
shade that
does not
fade in the
sun.
Genetically,
the two
cannot yet
be
differentiated,
and some
claim the
difference
occurs due
to
management
rather than
genetics,
though this
claim is
hotly
disputed.
Most black
foals are
usually born
a mousy grey
or dun
color. As
their foal
coat begins
to shed out,
their black
color will
show
through,
though in
some breeds
black foals
are born jet
black. For a
horse to be
considered
black, it
must be
completely
black except
for white
markings. A
sun-bleached
black horse
is still
black, even
though it
may appear
to be a dark
bay or
brown. A
visible
difference
between a
true black
and a dark
chestnut or
bay is seen
in the fine
hairs around
the eyes and
muzzle; on a
true black
these hairs
are black,
even if the
horse is
sun-bleached,
on other
colors, they
will be
lighter.
Brindle
- One of the
rarest
colors in
horses,
possibly
linked to
chimerism.
Characteristics
are any
color with
"zebra-like"
stripes, but
most common
is a brown
horse with
faint
yellowish
markings.
Buckskin- A bay horse with one copy of the cream gene, a dilution gene that 'dilutes' or fades the coat color to a yellow, cream, or gold while keeping the black points (mane, tail, legs).
Champagne: Produced by a different dilution gene than the cream gene. It lightens both skin and hair, but creates a metallic gold coat color with mottled skin and light colored eyes. Champagne horses are often confused with palomino, cremello, dun, or buckskins.
Cream dilution, an incomplete dominant gene that produces a partially diluted coat color with one copy of the allele and a full dilution with two copies. Colors produced include Palomino, Buckskin, Perlino, Cremello and Smoky Cream or Smoky black.
Cremello - A horse with a chestnut base coat and two cream genes that wash out almost all color until the horse is a pale cream or light tan color. Often called "white," they are not truly white horses, and they do not carry the white (W) gene. A cremello usually has blue eyes.
Dun: Yellowish or tan coat with primitive markings, sometimes called "dun factors:" a darker-colored mane and tail, a dorsal stripe along the back and occasionally faint horizontal zebra stripings on the upper legs and a possible transverse stripe across the withers. There are several variations of dun:
Grulla, Grullo or Blue Dun: A horse with a black base color and the dun gene. Coat is solid "mouse-colored" gray or silver with black or dark gray primitive markings.
Red dun: A chestnut base coat with dun factors. Coat is usually pale yellow or tan with chestnut (red) primitive markings.
"bay dun" or "zebra dun" are terms sometimes used to describe the classic dun color of yellow or tan with black primitive markings, used when necessary to distinguish it from red duns or grullos.
"Buckskin dun" describes a dun that also carries the cream gene dilution and has a coat of pale gold with black mane, tail, legs and primitive markings.
Leopard: There are a group of coat patterns caused by the leopard gene complex. It should be noted that not every horse with leopard genetics will exhibit hair coat spotting. However, even solid individuals will exhibit secondary characteristics such as vertically striped hooves, mottled skin around the eyes, lips, and genitalia, plus a white sclera of the eye. Several breeds of horse can boast leopard-spotted (a term used collectively for all patterns) individuals including the Knabstrup, Noriker, and the Appaloosa. There are several distinct leopard patterns:
blanket: white over the hip that may extend from the tail to the base of the neck. The spots inside the blanket (if present) are the same color as the horse's base coat.
varnish roan: a mix of body and white hairs that extends over the entire body--no relation to true roan
snowflake: white spots on a dark body. Typically the white spots increase in number and size as the horse ages.
leopard: dark spots of varying sizes over a white body.
few spot leopard: a nearly white horse from birth that retains color just above the hooves, the knees, 'armpits', mane and tail, wind pipe, and face
frost: similar to varnish but the white hairs are limited to the back, loins, and neck.
Other color modifiers
Sooty is a genetic modifier that causes dark hairs to be dispersed within the coat, darkening the whole coat.
Pangare is a modifier that is the opposite of sooty, it causes individual hairs to lighten, causing lightened areas on the muzzle, flank and belly of a horse.
"Flaxen" used only to describe the lightened mane and tail of a chestnut, has been proposed as a genetic modifier, particularly when it appears to be a trait of certain breeds. However, the genetic mechanism of this process has yet to be identified.
Markings and other unique identifiers
Main article: horse markings
White markings are present at birth and unique to each horse, making them useful in identifying individual animals. Markings usually have pink skin underneath them, though some faint markings may not, and white hairs may extend past the area of underlying pink skin. Though markings that overlie dark skin may appear to change, the underlying skin color and hair growing from pink skin will not. Horses may also be uniquely identified by an unusual eye color, whorls, brands and chestnuts.
Color breeds
Main article: color breed
Registries have opened that accept horses (and sometimes ponies and mules) of almost any breed or type, with color either the only requirement for registration or the primary criterion. These are called "color breeds." Unlike "true" horse breeds, there are few if any unique physical characteristics required, nor is the stud book limited to only certain breeds or offspring of previously registered horses. As a general rule, the color also does not always breed on (in some cases, due to genetic improbability), and offspring without the stated color are usually not eligible for recording with the color breed registry. The best-known color breed registries are for buckskins, palominos, and pintos.
Some "true" breeds also have color that usually breeds on as well as distinctive physical characteristics and a limited stud book. These horses are true breeds that are said to have a "color preference." They are not color breeds, and include the Friesian horse (must be black for mainstream registration), the Appaloosa (Leopard or other small spotting patterns) and the American Paint Horse. In some breeds, though not all, offspring of animals registered in these stud books can also be registered, sometimes with restrictions, even if they do not have the desired color.
Above friesian sporthorse stallion
Colour Black
Above: Lippazaner
Colour: Dapple gray
Above: Palamino
Above: Buckskin New Forest Pony
Above: Silver Dapple Horses
Above: Left young grey with few white hairs, chestnut and bay roan
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Above: Left pinto, right Appaloosa
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