Champagne gene
Encyclopedia
The champagne gene is a simple dominant allele
responsible for a number of rare horse
coat colors
. The most distinctive traits of horses with the champagne gene are the hazel eyes and pinkish, freckled skin, which are bright blue and bright pink at birth, respectively. The coat color is also affected: any hairs that would have been red are gold, and any hairs that would have been black are chocolate brown. If a horse inherits the champagne gene from either or both parents, a coat that would otherwise be chestnut
is instead gold champagne, with bay corresponding to amber champagne, seal brown
to sable champagne, and black
to classic champagne. A horse must have at least one champagne parent to inherit the champagne gene, for which there is now a DNA test.
Unlike the genes underlying tobiano
, dominant white
, frame overo
spotting and the Leopard complex
common to the Appaloosa
, the champagne gene does not affect the location of pigment-producing cells
in the skin. Nor does the champagne gene remove all pigment from the skin and hair, as in albinism
. Instead, the champagne gene produces traits known as hypomelanism, or dilution
. Champagne is not associated with any health defects. Other dilution genes in horses include the Cream gene
, Dun gene
, Pearl gene
and Silver dapple gene
. Horses affected by these genes can sometimes be confused with champagnes, but champagnes are genetically distinct. Champagnes are not palomino
s, buckskins, or grullo
s, nor does the word champagne indicate that a horse is a shiny or light shade of another coat color.
This gene and the associated coat colors are only known in American breeds, especially the American Cream Draft
, Tennessee Walker
and American Saddlebred
.
Champagne is a dominant
trait, based on a mutation in the SLC36A1 gene. A horse with either one or two champagne gene
s will show the effects of the gene equally. However, if a horse is homozygous for a dominant gene, it will always pass the gene on to all of its offspring, while if the horse is heterozygous for the gene, the offspring will not always inherit the color. Horses with the champagne gene may also carry other coat color genes that affect their phenotype
, or outward color.
Horses with the champagne gene have a lightened hair coat and specific eye and skin color traits. Black pigment in the coat, if present, is lightened to chocolate, while red pigment is lightened to gold. The precise champagne dilute coat color produced depends on the underlying base coat color. The effects of champagne plus additional coat color genes have their own distinct vocabulary and appearances;
It is difficult to distinguish between homozygous and heterozygous champagne, which is different from incomplete dominant
dilutions such as the cream gene
. However the 2008 study that mapped the gene and identified it as a dominant trait noted in passing that homozygotes may have less mottling or a slightly lighter hair color. The authors of this study noted that
The following are considered the most "basic" champagne coat colors:
Classic champagne is, as its name suggests, the coat color most associated with the champagne gene. It is produced by the action of champagne on a black
coat. The body coat is chocolate, the mane and tail a darker shade. The legs may also be slightly darker. The overall effect has also been described as lilac, dark taupe, and even green. This color is most often misclassified as grullo
, and in the past was sometimes called "lilac dun."
Sable champagne is produced by the action of champagne on a seal brown
coat. It is visually difficult to distinguish from classic champagne, and in the past was confirmed by a DNA test negative for the recessive black (a) allele at Agouti
. Today, a test for seal brown can confirm this color.
Amber champagne is produced by the action of champagne on a bay coat. The coat is gold with chocolate points
. Just as there are varying shades of bay, the gold body coat may vary in shade as well. The legs are often lighter than the mane and tail, and the colored points may be difficult to see. The mane and tail may also have "frosting" or light edges, a trait that also occurs in bay duns
and some buckskins. Amber champagne can be confused with buckskin or bay dun.
Gold champagne is produced by the action of champagne on a chestnut
coat. The coat is gold, and the mane and tail are typically ivory. In some cases, the mane and tail may be self-colored, matching the body coat. These gold champagnes are sometimes called "dark gold" and may be an all-over apricot shade. Dark gold champagnes can be confused with red dun
, while those with paler manes and tails were historically called "pumpkin-skinned palomino
s."
Apart from the unique shades, there are several qualities of the champagne coat that may be used to help identify them. Champagne coats often have an unusual sheen. This sheen makes champagnes difficult to photograph accurately, as the appearance of the coat depends on the lighting. Not all champagne horses have this sheen, and there are many extremely shiny non-champagne horses, so a "sheen" in and of itself does not indicate the champagne gene. The coat may also exhibit reverse dappling, though this is also an unreliable indicator.
The color of the skin is the single most important visual identifier of champagne horses: in the adult horse, the skin is "pink with abundant dark freckles, except under white markings." The freckles - not mottles, splotches, specks, or blotches - are dark and may have a purple cast, and are small and numerous. By comparison, mottling associated with the Leopard complex
is large and blocky alternations between true black or charcoal-colored skin and pigmentless-pink skin. The skin of cremellos and perlinos
is pigmented-pink, and exhibit a scant few tiny black specks. Homozygous pearls
and pearl-cream combinations also exhibit some freckling of the skin, however this is muted in comparison to the freckles of champagne skin. The skin may exhibit an overall lavender tone. The color qualities of the skin are most evident around the eyes and muzzle, under the tail, and on the udder or sheath.
The eyes of an adult champagne horse are most often described as hazel or amber. In the newborn or very young foal
, the eyes are bright blue to blue-green and the skin is bright pink. The champagne blue foal eye is creamier than other types of blue eye such as the bright, unpigmented blue seen on some pinto horse
s.
In the past, some breeders and horse owners had concerns that horses with light-colored skin and eyes were not healthy. However, the lightening of these parts of the horse due to the champagne gene is not known to be linked to any health or genetic defects. While horses with white markings
may sunburn on exposed unpigmented skin, the freckled-pink skin of a champagne horse is said to tan instead. In addition, the color of the hoof has no bearing on its strength.
.
Horses with both the champagne gene and the cream gene
are the most common combination. The cream gene is responsible for the palomino
, buckskin and cremello coat colors, and is a dose-dependent or incomplete dominant, meaning that a horse with only one copy is visibly different from a horse with two copies of the gene. A single copy of the cream gene dilutes red pigment in the coat to gold or yellow, and has a slight effect on the skin and eye color. The black pigment is lightened little, if at all. Two copies of the cream gene dilute both red and black pigments in the hair to cream or ivory, dilute the skin to a rosy-pink and the eyes to pale blue. The cream gene and champagne gene have an additive or enhancing interaction. Horses with the champagne gene and a single cream gene typically have lighter yellowish or blue eyes and paler, more faintly-freckled skin.
Horses with both the champagne gene and the dun gene
are also well-recorded. The dun gene is responsible for flat, diluted coat colors and vivid primitive markings
. Bay dun is thought to be the wildtype horse coat color. Dun does not affect skin or eye color, but dilutes red pigment to yellow and black pigment to slate gray. Champagne horses with the dun gene will have slightly further-diluted coats compared to non-dun champagnes, and will always exhibit striking primitive markings, such as a dorsal stripe and zebra-like stripes on the legs.
Naming schemes are much the same as with champagne-cream combinations. Champagne-dun combinations retain their champagne eye and skin traits. The coats are distinguishable from non-champagne duns in that they are several shades lighter, black pigment is chocolate rather than slate, and they may exhibit a sheen. The coats are distinguishable from non-dun champagnes in the presence of primitive markings and a flatter tone.
The silver dapple gene
in horses does not affect the eyes, skin, or red pigment. Chestnuts are unaffected, but in bay, seal brown, and black horses, the black pigment is diluted to a chocolate or silver. The mane and tail are most commonly affected. Champagne horses with the silver gene will retain their champagne skin and eye traits, but the black pigment will be further diluted. Silvers vary tremendously in shade and so defining a "typical" example is difficult.
The champagne gene, in combination with some white patterning genes, can also produce unexpected phenotypes. Horses with the leopard gene
or Appaloosa
s exhibit starkly mottled skin around the muzzle, eyes, anus and sheath or udder. Most commonly, the mottling is blocky patches of normal, black skin and unpigmented pink. When a horse has both the leopard gene and the champagne gene, the champagne-associated skin is present only where the skin would be otherwise black.
In combination with gray
, champagne produces very unusual coat behavior. Typically, gray horses are born a dark shade of their natural color, and begin to develop gray hairs around the eyes and muzzle. With each shed, the coat becomes lighter and lighter. Many older grays develop the "fleabitten" trait, in which small, interspersed flecks of red occur and often increase in density with age, even as the rest of the coat loses pigment. A few grays will also develop vitiligo
in which the skin also progressively loses pigment. When a horse carries both gray and champagne, additional traits occur: Gray-champagnes are born with darker coats than the usual champagne foal, but still exhibiting the expected bright blue eyes and pink skin. The freckling that develops on the skin is also exceptionally dark and dense. Gray-champagnes appear more likely to experience vitiligo. The most unexpected quality of gray-champagnes is the intensity of the fleabitten trait. Flecks of champagne-colored hair are thickly interspersed in the unpigmented white hairs.
, Pearl gene
, and Silver dapple gene
.
Palomino or Chestnut vs. Gold champagne: The most common confusion, as both of these genetically distinct coat colors feature a gold or yellow coat and ivory or cream mane and tail. As adults, the pinkish freckled skin and hazel eyes indicate gold champagne, while gray or black skin and light or dark brown eyes indicate palomino. At birth, palominos may have pink skin and blue or grey eyes, however these darken within days or weeks. Occasionally, chestnuts
are also born with blue eyes and pink skin, and as gold champagnes often have chestnut-colored foal coats, the two can be difficult to distinguish. Again, the skin and eyes of the chestnut will darken quickly. In all cases, pedigrees can provide important information. Palominos will have a parent that is palomino, buckskin, smoky black, or blue-eyed cream
. Champagnes will have a champagne parent.
Buckskin and Bay dun vs. Amber champagne: All three of these genetically distinct coat colors feature a lighter bronze or tan coat with darker points. As adults, the pinkish freckled skin and hazel eyes indicate amber champagne, while gray or black skin and light or dark brown eyes indicate buckskin or bay dun. Duns do not exhibit unusually-colored skin, though buckskins, like palominos, may be born with blue eyes that darken within days or weeks. In the adult, the points of a buckskin or bay dun will be black, not chocolate as in the amber champagne. Bay dun horses also exhibit primitive markings
, especially a dorsal stripe, though amber duns will also possess these marks. The eyes and skin remain the best identifying feature. Buckskins, like palominos, will a parent that is palomino
, buckskin, smoky black, or blue-eyed cream
. Bay duns will have a parent that is bay dun, red dun, or grullo. Champagnes will have a champagne parent.
Grullo
vs. Classic champagne or Sable champagne: Classic and sable champagnes are difficult to distinguish without a DNA test. Grullos and classic champagnes are both dilutions of the black
coat, and typically have black or dark points and dove-gray coats. However, Grullos, in absence of any other dilution factors, are not born with pink skin and blue eyes, while champagnes always have these traits. As adults, grullos will retain their dark brown eyes and black skin, while champagnes have pinkish freckled skin and hazel eyes. Grullos, like all duns, will possess primitive markings
, and their coats are typically a cooler, slate shade, while classic and sable champagnes are chocolate-toned. The points and primitive markings on the grullo are black, while the points on classic and sable champagnes are brown. Grullos will have dun
ancestry and champagnes will have champagne ancestry.
Red dun vs. Dark gold champagne: Some gold champagnes have darker bodies and self-colored manes and tails. These horses may resemble red duns, however red duns have distinct primitive markings
and do not possess pinkish freckled skin or hazel eyes as adults, nor the bright pink skin and bright blue eyes of champagne foals.
Blue-eyed cream vs. Champagne: Blue-eyed cream is a collective term for any horse homozygous for the Cream gene
(cremello, perlino, etc.). Blue-eyed creams, as their name suggests, have blue eyes from birth through adulthood and also have pink skin. Typically their blue eyes are quite pale, and are easy to distinguish from the sky blue eyes of champagne foals and the hazel eyes of adult champagnes. Their skin may have a scant few black flecks, but the abundant freckles of champagne skin are absent. The respective shades of pink skin and blue eyes are slightly different.
Leopard vs. Champagne: The Leopard complex
is responsible for the spotted coat of the Appaloosa
and other breeds. Even when a spotted hair coat is absent, other traits produced include mottled skin and a white sclera
around the eye but generally the eye itself is dark brown. These mottles are alternations between unpigmented pink skin and pigmented skin, which is usually black (thus the mottles are black on a pink background). The mottles are substantially larger than the freckles of champagne skin, and leopard complex horses do not necessarily have light eyes.
Pearl vs. Champagne: In the homozygous state, or when combined with cream, the Pearl gene
produces a diluted apricot to buff color, pale eyes and pale skin. Heterozygous pearls (one copy of the gene) often exhibit dark skin with some pinkish freckles, while homozygous pearls (two copies of the gene) have champagne-like skin. The freckles on homozygous pearls and pearl-creams are pale and muted.
horses are gold champagne. The champagne gene is also found in the Tennessee Walking Horse, American Saddlebred
, Missouri Fox Trotter
, Racking horse
, Kentucky Mountain Saddle Horse
, Spanish Mustang
, American Quarter Horse
, American Paint Horse
, Appaloosa
and Miniature horse
breeds.
. It is widespread among American horses, and has likely been present in the genepool for more than a century. The Palomino
Horse Breeders Association (PHBA), which registers "palomino" horses based on appearance, includes allowances for freckle-skinned and hazel-eyed palominos. Furthermore, while the registry typically disallows horses with pink skin, it allows American Saddlebred
s with skin of any color to be registered. The PHBA was incorporated in 1941. Further back, the foundation mare of the American Cream Draft
horse breed, "Old Granny", was born around 1905 in Iowa. Her cream-colored coat, pink skin and amber eyes are defining standards for the breed of her descendants, which are now known to be gold champagne.
The superficial similarities between gold champagne and palomino, and amber champagne and buckskin, may account for the relatively recent identification of champagne as a separate trait. Gold champagnes were sometimes called "pumpkin-skinned palomino." Classic champagnes, which lack the primitive markings
of true duns, were similarly called "lilac duns." The mare that brought the champagne coat color family to the attention of modern researchers was a Tennessee Walking Horse named "Champagne Lady Diane" born in 1969. A classic champagne, Champagne Lady Diane was described as "a genetic color accident" after her hairs were sent to several universities, although current evidence suggests that the champagne gene predates Champagne Lady Diane.
It was not until many years after the name "champagne" was ascribed to Champagne Lady Diane that the term appeared in scientific literature. It was first studied and described by Sponenberg and Bowling in 1996. They studied the ratio of champagne-to-non-champagne offspring of champagne horses, and designated the causal mutation as the dominant Ch allele on the hypothetical Champagne locus
.
is on exon
2 of the SLC36A1
gene, which is on chromosome
14 (ECA14); a single nucleotide polymorphism
(SNP) exchanges a C for a G at base 76 (c.188C>G) resulting in a missense mutation
. On a protein level, this SNP is predicted to result in the replacement of a threonine
with arginine
at amino acid
63 (T63R). SLC36A1 is not associated with pigmentation phenotypes in other species, and its role in most tissues is poorly understood. SLC36A1 is a member of a loosely-united group of over 300 proteins responsible for active transport
and facilitated diffusion
called the Solute carrier family
. Other members of this family include SLC45A2
, which is responsible for pigmentation variations of many types in humans, as well as the cream
coat color in horses; and SLC24A5
, which is responsible for the Golden dilution in mice
.
Dilution gene
s such as champagne and cream
affect the nature or density of the pigments produced by melanocyte
s. On the other hand, genes in horses which produce white spotting, such as Frame
and Sabino1
, interrupt or limit the migration of melanocyte
s from the neural crest
. In other words, the skin, eyes, and hair of horses with the champagne mutation do not lack melanocytes, melanosomes, or melanins, but rather exhibit hypomelanism. However, the specific role of SLC36A1 in pigmentation and how the champagne coat colors are created on a molecular level is not known. The researchers who identified the mutation in 2008 suggested that melanosome
pH
may be affected, which in turn might affect the processing of tyrosine
, a critical element of melanogenesis.
There are two alleles in this series: the recessive, wildtype allele ch and the dominant CH. The CH allele represents the T63R SLC36A1 mutation.
The DNA test for champagne detects the c.188C>G mutation on SLC36A1.
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
responsible for a number of rare horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
coat colors
Equine coat color
Horses exhibit a diverse array of coat colors and distinctive markings. A specialized vocabulary has evolved to describe them.While most horses remain the same color throughout life, a few, over the course of several years, will develop a different coat color from that with which they were born...
. The most distinctive traits of horses with the champagne gene are the hazel eyes and pinkish, freckled skin, which are bright blue and bright pink at birth, respectively. The coat color is also affected: any hairs that would have been red are gold, and any hairs that would have been black are chocolate brown. If a horse inherits the champagne gene from either or both parents, a coat that would otherwise be chestnut
Chestnut (coat)
Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Genetically and visually, chestnut is characterized by the absolute absence of true black hairs...
is instead gold champagne, with bay corresponding to amber champagne, seal brown
Seal brown (horse)
Seal brown is a hair coat color of horses characterized by a near-black body color; with black points, the mane, tail and legs; but also reddish or tan areas around the eyes, muzzle, behind the elbow and in front of the stifle...
to sable champagne, and black
Black (horse)
Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and novices frequently mistake dark chestnuts or bays for black. However, some breeds of horses, such as the Friesian horse, Murgese and Ariegeois are almost exclusively black...
to classic champagne. A horse must have at least one champagne parent to inherit the champagne gene, for which there is now a DNA test.
Unlike the genes underlying tobiano
Tobiano
Tobiano is a spotted color pattern commonly seen in Pinto horses, produced by a dominant gene. The tobiano gene produces white-haired, pink-skinned patches on a base coat color. The coloration is present from birth and does not change throughout the horse's lifetime, unless the horse also carries...
, dominant white
White (horse)
White horses are born white and stay white throughout their life. White horses may have brown, blue, or hazel eyes. "True white" horses, especially those that carry one of the dominant white genes, are rare...
, frame overo
Lethal white syndrome
Lethal white syndrome , also called overo lethal white syndrome , lethal white overo , and overo lethal white foal syndrome , is an autosomal genetic disorder most prevalent in the American Paint Horse...
spotting and the Leopard complex
Leopard complex
The leopard complex is a group of genetically-related coat patterns in horses. These patterns range from progressive increases in interspersed white hair similar to graying or roan to distinctive, Dalmatian-like leopard spots on a white coat. Secondary characteristics associated with the leopard...
common to the Appaloosa
Appaloosa
The Appaloosa is a horse breed best known for its colorful leopard-spotted coat pattern. There is a wide range of body types within the breed, stemming from the influence of multiple breeds of horses throughout its history. Each horse's color pattern is genetically the result of various spotting...
, the champagne gene does not affect the location of pigment-producing cells
Melanocyte
-External links: - "Eye: fovea, RPE" - "Integument: pigmented skin"...
in the skin. Nor does the champagne gene remove all pigment from the skin and hair, as in albinism
Albinism
Albinism is a congenital disorder characterized by the complete or partial absence of pigment in the skin, hair and eyes due to absence or defect of an enzyme involved in the production of melanin...
. Instead, the champagne gene produces traits known as hypomelanism, or dilution
Dilution gene
Dilution gene is a popular term for any one of a number of genes that act to create a lighter coat color in living creatures. There are many examples of such genes:-General:...
. Champagne is not associated with any health defects. Other dilution genes in horses include the Cream gene
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
, Dun gene
Dun gene
The dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
, Pearl gene
Pearl gene
The Pearl gene, also known as the "Barlink factor," is a dilution gene that somewhat resembles the cream gene and the champagne gene, but is neither. It is a somewhat rare dilution gene found in the American Quarter Horse, American Paint Horse, and Peruvian Paso. The same mutation appears in...
and Silver dapple gene
Silver dapple gene
The silver dapple gene is a dilution gene that affects the black base coat color. It will typically dilute a black mane and tail to flaxen, and a black body to a shade of brown or chocolate. It is responsible for a group of coat colors in horses called "silver dapple" in the west, or "taffy" in...
. Horses affected by these genes can sometimes be confused with champagnes, but champagnes are genetically distinct. Champagnes are not palomino
Palomino
Palomino is a coat color in horses, consisting of a gold coat and white mane and tail. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" base coat...
s, buckskins, or grullo
Grullo
Grullo is a color of horses in the dun family, characterized by tan-gray or mouse-colored hairs on the body, often with shoulder and dorsal stripes and black barring on the lower legs. In this coloration each individual hair is mouse-colored, unlike a roan which is composed of a mixture of dark and...
s, nor does the word champagne indicate that a horse is a shiny or light shade of another coat color.
This gene and the associated coat colors are only known in American breeds, especially the American Cream Draft
American Cream Draft
The American Cream Draft is a rare draft horse breed, the only such breed developed in the United States that is still in existence. It is known for its cream color and amber eyes, produced by the champagne gene. The only other color found in the breed is chestnut, and the cream color produced by...
, Tennessee Walker
Tennessee Walker
The Tennessee Walker or Tennessee Walking Horse is a breed of riding horse. The breed was originally bred in the Southern United States to carry the owners of plantations around their lands...
and American Saddlebred
American Saddlebred
The American Saddlebred, formerly known as the American Saddle Horse, is a breed of horse that was developed in Kentucky by plantation owners. Today, in the horse show world, they are most commonly seen under saddle in Saddle seat style riding, and in various types of driving, including pleasure...
.
Coat colors
Champagne is a dominant
Dominance relationship
Dominance in genetics is a relationship between two variant forms of a single gene, in which one allele masks the effect of the other in influencing some trait. In the simplest case, if a gene exists in two allelic forms , three combinations of alleles are possible: AA, AB, and BB...
trait, based on a mutation in the SLC36A1 gene. A horse with either one or two champagne gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s will show the effects of the gene equally. However, if a horse is homozygous for a dominant gene, it will always pass the gene on to all of its offspring, while if the horse is heterozygous for the gene, the offspring will not always inherit the color. Horses with the champagne gene may also carry other coat color genes that affect their phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
, or outward color.
Horses with the champagne gene have a lightened hair coat and specific eye and skin color traits. Black pigment in the coat, if present, is lightened to chocolate, while red pigment is lightened to gold. The precise champagne dilute coat color produced depends on the underlying base coat color. The effects of champagne plus additional coat color genes have their own distinct vocabulary and appearances;
It is difficult to distinguish between homozygous and heterozygous champagne, which is different from incomplete dominant
Dominance relationship
Dominance in genetics is a relationship between two variant forms of a single gene, in which one allele masks the effect of the other in influencing some trait. In the simplest case, if a gene exists in two allelic forms , three combinations of alleles are possible: AA, AB, and BB...
dilutions such as the cream gene
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
. However the 2008 study that mapped the gene and identified it as a dominant trait noted in passing that homozygotes may have less mottling or a slightly lighter hair color. The authors of this study noted that
The following are considered the most "basic" champagne coat colors:
Classic champagne is, as its name suggests, the coat color most associated with the champagne gene. It is produced by the action of champagne on a black
Black (horse)
Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and novices frequently mistake dark chestnuts or bays for black. However, some breeds of horses, such as the Friesian horse, Murgese and Ariegeois are almost exclusively black...
coat. The body coat is chocolate, the mane and tail a darker shade. The legs may also be slightly darker. The overall effect has also been described as lilac, dark taupe, and even green. This color is most often misclassified as grullo
Grullo
Grullo is a color of horses in the dun family, characterized by tan-gray or mouse-colored hairs on the body, often with shoulder and dorsal stripes and black barring on the lower legs. In this coloration each individual hair is mouse-colored, unlike a roan which is composed of a mixture of dark and...
, and in the past was sometimes called "lilac dun."
Sable champagne is produced by the action of champagne on a seal brown
Seal brown (horse)
Seal brown is a hair coat color of horses characterized by a near-black body color; with black points, the mane, tail and legs; but also reddish or tan areas around the eyes, muzzle, behind the elbow and in front of the stifle...
coat. It is visually difficult to distinguish from classic champagne, and in the past was confirmed by a DNA test negative for the recessive black (a) allele at Agouti
Agouti signalling peptide
Agouti signalling peptide, a product of the Agouti gene, is a peptide consisting of 131 amino acids. Its discovery was published in 1994 in the scientific journal Nature where its functional properties were described...
. Today, a test for seal brown can confirm this color.
Amber champagne is produced by the action of champagne on a bay coat. The coat is gold with chocolate points
Point (coat color)
Point coloration refers to animal coat coloration with a pale body and relatively darker extremities, i.e. the face, ears, feet, tail, and scrotum...
. Just as there are varying shades of bay, the gold body coat may vary in shade as well. The legs are often lighter than the mane and tail, and the colored points may be difficult to see. The mane and tail may also have "frosting" or light edges, a trait that also occurs in bay duns
Dun gene
The dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
and some buckskins. Amber champagne can be confused with buckskin or bay dun.
Gold champagne is produced by the action of champagne on a chestnut
Chestnut (coat)
Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Genetically and visually, chestnut is characterized by the absolute absence of true black hairs...
coat. The coat is gold, and the mane and tail are typically ivory. In some cases, the mane and tail may be self-colored, matching the body coat. These gold champagnes are sometimes called "dark gold" and may be an all-over apricot shade. Dark gold champagnes can be confused with red dun
Dun gene
The dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
, while those with paler manes and tails were historically called "pumpkin-skinned palomino
Palomino
Palomino is a coat color in horses, consisting of a gold coat and white mane and tail. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" base coat...
s."
Apart from the unique shades, there are several qualities of the champagne coat that may be used to help identify them. Champagne coats often have an unusual sheen. This sheen makes champagnes difficult to photograph accurately, as the appearance of the coat depends on the lighting. Not all champagne horses have this sheen, and there are many extremely shiny non-champagne horses, so a "sheen" in and of itself does not indicate the champagne gene. The coat may also exhibit reverse dappling, though this is also an unreliable indicator.
Skin, eyes, and hooves
Leopard complex
The leopard complex is a group of genetically-related coat patterns in horses. These patterns range from progressive increases in interspersed white hair similar to graying or roan to distinctive, Dalmatian-like leopard spots on a white coat. Secondary characteristics associated with the leopard...
is large and blocky alternations between true black or charcoal-colored skin and pigmentless-pink skin. The skin of cremellos and perlinos
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
is pigmented-pink, and exhibit a scant few tiny black specks. Homozygous pearls
Pearl gene
The Pearl gene, also known as the "Barlink factor," is a dilution gene that somewhat resembles the cream gene and the champagne gene, but is neither. It is a somewhat rare dilution gene found in the American Quarter Horse, American Paint Horse, and Peruvian Paso. The same mutation appears in...
and pearl-cream combinations also exhibit some freckling of the skin, however this is muted in comparison to the freckles of champagne skin. The skin may exhibit an overall lavender tone. The color qualities of the skin are most evident around the eyes and muzzle, under the tail, and on the udder or sheath.
The eyes of an adult champagne horse are most often described as hazel or amber. In the newborn or very young foal
Foal
A foal is an equine, particularly a horse, that is one year old or younger. More specific terms are colt for a male foal and filly for a female foal, but these terms are used until the horse is age three or four. When the foal is nursing from its dam , it may also be called a suckling...
, the eyes are bright blue to blue-green and the skin is bright pink. The champagne blue foal eye is creamier than other types of blue eye such as the bright, unpigmented blue seen on some pinto horse
Pinto horse
A pinto horse has a coat color that consists of large patches of white and any other color. The distinction between "pinto" and "solid" can be tenuous, as so-called "solid" horses frequently have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto...
s.
In the past, some breeders and horse owners had concerns that horses with light-colored skin and eyes were not healthy. However, the lightening of these parts of the horse due to the champagne gene is not known to be linked to any health or genetic defects. While horses with white markings
Horse markings
Markings on horses usually are distinctive white areas on an otherwise dark base coat color. Most horses have some markings, and they help to identify the horse as a unique individual. Markings are present at birth and do not change over the course of the horse's life...
may sunburn on exposed unpigmented skin, the freckled-pink skin of a champagne horse is said to tan instead. In addition, the color of the hoof has no bearing on its strength.
Interaction with other coat color factors
The presence of other coat color modifying alleles has no effect on whether or not a horse has the champagne trait. However, different traits may interact; they may suppress, enhance, obscure or cancel out various tell-tale clues to the genetic identity of a coat color. Coat colors involving multiple genes often have an unexpected appearance and unique terminology. This type of genetic interaction is called epistasisEpistasis
In genetics, epistasis is the phenomenon where the effects of one gene are modified by one or several other genes, which are sometimes called modifier genes. The gene whose phenotype is expressed is called epistatic, while the phenotype altered or suppressed is called hypostatic...
.
Horses with both the champagne gene and the cream gene
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
are the most common combination. The cream gene is responsible for the palomino
Palomino
Palomino is a coat color in horses, consisting of a gold coat and white mane and tail. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" base coat...
, buckskin and cremello coat colors, and is a dose-dependent or incomplete dominant, meaning that a horse with only one copy is visibly different from a horse with two copies of the gene. A single copy of the cream gene dilutes red pigment in the coat to gold or yellow, and has a slight effect on the skin and eye color. The black pigment is lightened little, if at all. Two copies of the cream gene dilute both red and black pigments in the hair to cream or ivory, dilute the skin to a rosy-pink and the eyes to pale blue. The cream gene and champagne gene have an additive or enhancing interaction. Horses with the champagne gene and a single cream gene typically have lighter yellowish or blue eyes and paler, more faintly-freckled skin.
- Gold cream or Ivory champagne refers to an otherwise-chestnutChestnut (coat)Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Genetically and visually, chestnut is characterized by the absolute absence of true black hairs...
coat affected by the champagne gene and a single copy of the cream geneCream geneThe cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
. The mane, tail, and coat of gold creams are typically ivory and difficult to distinguish from cremello, other than by the skin and eyes. - Amber cream, similarly, is an otherwise-bay coat affected by the champagne gene and a single copy of the cream gene. The mane and tail of a typical amber cream are a warm yellowish-brown and are often frosted. The legs may also be a light chocolate brown, but need not be. The body coat is a shade of ivory, usually darker than a gold cream. Their points are substantially darker than those of a perlino, and they have champagne skin and eye traits.
- Sable cream is a seal brownSeal brown (horse)Seal brown is a hair coat color of horses characterized by a near-black body color; with black points, the mane, tail and legs; but also reddish or tan areas around the eyes, muzzle, behind the elbow and in front of the stifle...
coat affected by champagne and a single copy of the cream gene. Sable creams may more closely resemble amber cream or classic cream. Most are several shades darker, with a cooler hue, than amber creams. - Classic cream is a blackBlack (horse)Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and novices frequently mistake dark chestnuts or bays for black. However, some breeds of horses, such as the Friesian horse, Murgese and Ariegeois are almost exclusively black...
coat affected by champagne and a single copy of the cream gene. Classic cream coats should resemble classic champagne shades, being only slightly lightened by the cream gene. Their coats may have a cooler hue. - Double cream champagne is a coat of any color affected by champagne and both copies of the cream gene. Unlike the coat colors associated with only a single cream gene, double cream champagnes (respectively prefixed with "gold," "amber," etc.) retain no obvious champagne traits. Their skin is clear pink without freckling, and the eyes are pale blue. The terms "cremello champagne", "perlino champagne" and so forth are also acceptable.
Horses with both the champagne gene and the dun gene
Dun gene
The dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
are also well-recorded. The dun gene is responsible for flat, diluted coat colors and vivid primitive markings
Primitive markings
Primitive markings among domestic horses are a group of hair coat markings and qualities associated with primitive breeds, and the dun coat color family in particular. All dun horses possess at least the dorsal stripe but the presence of the other primitive markings varies...
. Bay dun is thought to be the wildtype horse coat color. Dun does not affect skin or eye color, but dilutes red pigment to yellow and black pigment to slate gray. Champagne horses with the dun gene will have slightly further-diluted coats compared to non-dun champagnes, and will always exhibit striking primitive markings, such as a dorsal stripe and zebra-like stripes on the legs.
Naming schemes are much the same as with champagne-cream combinations. Champagne-dun combinations retain their champagne eye and skin traits. The coats are distinguishable from non-champagne duns in that they are several shades lighter, black pigment is chocolate rather than slate, and they may exhibit a sheen. The coats are distinguishable from non-dun champagnes in the presence of primitive markings and a flatter tone.
- Gold dun refers to an otherwise-chestnut coat affected by both the champagne gene and dun geneDun geneThe dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
. The mane and tail may be ivory or self-colored; the body coat ranges from a warm cream to apricot color with primitive markings a shade darker. The coat is substantially paler and more "yellow" than that of a chestnut dun, and flatter than that of a gold champagne. - Amber dun refers to an otherwise-bay coat affected by both the champagne gene and dun gene. The mane and tail and primitive markings are warm chocolate brown with a buff tan-colored body. The legs may, or may not, be dark as well.
- Sable dun refers to an otherwise-seal brown coat affected by both the champagne gene and dun gene. The points are chocolate-colored and the coat is darker than the amber dun.
- Classic dun or Classic grulla refers to an otherwise-black coat affected by both the champagne gene and dun gene. The coat possesses more cool slate-gray tones than a classic champagne, while the points are warmer than a grulla.
The silver dapple gene
Silver dapple gene
The silver dapple gene is a dilution gene that affects the black base coat color. It will typically dilute a black mane and tail to flaxen, and a black body to a shade of brown or chocolate. It is responsible for a group of coat colors in horses called "silver dapple" in the west, or "taffy" in...
in horses does not affect the eyes, skin, or red pigment. Chestnuts are unaffected, but in bay, seal brown, and black horses, the black pigment is diluted to a chocolate or silver. The mane and tail are most commonly affected. Champagne horses with the silver gene will retain their champagne skin and eye traits, but the black pigment will be further diluted. Silvers vary tremendously in shade and so defining a "typical" example is difficult.
- Amber silver refers to an otherwise-bay coat affected by both the champagne gene and silver gene. The interaction of these two genes - one diluting black to warm chocolate and red to gold, and the other diluting black further to silver - creates an unexpected phenotype. The more closely resembles colors in the red family, mostly deprived of black pigment. The mane and tail may be self-colored, and the coat is buttery and pale.
- Classic silver refers to an otherwise-black coat affected by both the champagne gene and silver gene. The darkest examples resemble classic champagnes with a silvery mane and tail. The palest are a very pale pewter. Some have warm chocolate tones, others do not.
The champagne gene, in combination with some white patterning genes, can also produce unexpected phenotypes. Horses with the leopard gene
Leopard complex
The leopard complex is a group of genetically-related coat patterns in horses. These patterns range from progressive increases in interspersed white hair similar to graying or roan to distinctive, Dalmatian-like leopard spots on a white coat. Secondary characteristics associated with the leopard...
or Appaloosa
Appaloosa
The Appaloosa is a horse breed best known for its colorful leopard-spotted coat pattern. There is a wide range of body types within the breed, stemming from the influence of multiple breeds of horses throughout its history. Each horse's color pattern is genetically the result of various spotting...
s exhibit starkly mottled skin around the muzzle, eyes, anus and sheath or udder. Most commonly, the mottling is blocky patches of normal, black skin and unpigmented pink. When a horse has both the leopard gene and the champagne gene, the champagne-associated skin is present only where the skin would be otherwise black.
In combination with gray
Gray (horse)
Gray or grey is a coat color of horses characterized by progressive silvering of the colored hairs of the coat. Most gray horses have black skin and dark eyes; unlike many depigmentation genes, gray does not affect skin or eye color Their adult hair coat is white, dappled, or white intermingled...
, champagne produces very unusual coat behavior. Typically, gray horses are born a dark shade of their natural color, and begin to develop gray hairs around the eyes and muzzle. With each shed, the coat becomes lighter and lighter. Many older grays develop the "fleabitten" trait, in which small, interspersed flecks of red occur and often increase in density with age, even as the rest of the coat loses pigment. A few grays will also develop vitiligo
Vitiligo
Vitiligo is a condition that causes depigmentation of sections of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress,...
in which the skin also progressively loses pigment. When a horse carries both gray and champagne, additional traits occur: Gray-champagnes are born with darker coats than the usual champagne foal, but still exhibiting the expected bright blue eyes and pink skin. The freckling that develops on the skin is also exceptionally dark and dense. Gray-champagnes appear more likely to experience vitiligo. The most unexpected quality of gray-champagnes is the intensity of the fleabitten trait. Flecks of champagne-colored hair are thickly interspersed in the unpigmented white hairs.
Champagne mimics
Many coat color modifying genes affect the skin and eyes as well as the coat color. Several of these may be confused with champagne. Today, when the visible cues are insufficient, horses can be DNA tested for the champagne gene, Cream geneCream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
, Pearl gene
Pearl gene
The Pearl gene, also known as the "Barlink factor," is a dilution gene that somewhat resembles the cream gene and the champagne gene, but is neither. It is a somewhat rare dilution gene found in the American Quarter Horse, American Paint Horse, and Peruvian Paso. The same mutation appears in...
, and Silver dapple gene
Silver dapple gene
The silver dapple gene is a dilution gene that affects the black base coat color. It will typically dilute a black mane and tail to flaxen, and a black body to a shade of brown or chocolate. It is responsible for a group of coat colors in horses called "silver dapple" in the west, or "taffy" in...
.
Palomino or Chestnut vs. Gold champagne: The most common confusion, as both of these genetically distinct coat colors feature a gold or yellow coat and ivory or cream mane and tail. As adults, the pinkish freckled skin and hazel eyes indicate gold champagne, while gray or black skin and light or dark brown eyes indicate palomino. At birth, palominos may have pink skin and blue or grey eyes, however these darken within days or weeks. Occasionally, chestnuts
Chestnut (coat)
Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Genetically and visually, chestnut is characterized by the absolute absence of true black hairs...
are also born with blue eyes and pink skin, and as gold champagnes often have chestnut-colored foal coats, the two can be difficult to distinguish. Again, the skin and eyes of the chestnut will darken quickly. In all cases, pedigrees can provide important information. Palominos will have a parent that is palomino, buckskin, smoky black, or blue-eyed cream
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
. Champagnes will have a champagne parent.
Buckskin and Bay dun vs. Amber champagne: All three of these genetically distinct coat colors feature a lighter bronze or tan coat with darker points. As adults, the pinkish freckled skin and hazel eyes indicate amber champagne, while gray or black skin and light or dark brown eyes indicate buckskin or bay dun. Duns do not exhibit unusually-colored skin, though buckskins, like palominos, may be born with blue eyes that darken within days or weeks. In the adult, the points of a buckskin or bay dun will be black, not chocolate as in the amber champagne. Bay dun horses also exhibit primitive markings
Primitive markings
Primitive markings among domestic horses are a group of hair coat markings and qualities associated with primitive breeds, and the dun coat color family in particular. All dun horses possess at least the dorsal stripe but the presence of the other primitive markings varies...
, especially a dorsal stripe, though amber duns will also possess these marks. The eyes and skin remain the best identifying feature. Buckskins, like palominos, will a parent that is palomino
Palomino
Palomino is a coat color in horses, consisting of a gold coat and white mane and tail. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" base coat...
, buckskin, smoky black, or blue-eyed cream
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
. Bay duns will have a parent that is bay dun, red dun, or grullo. Champagnes will have a champagne parent.
Grullo
Grullo is a color of horses in the dun family, characterized by tan-gray or mouse-colored hairs on the body, often with shoulder and dorsal stripes and black barring on the lower legs. In this coloration each individual hair is mouse-colored, unlike a roan which is composed of a mixture of dark and...
vs. Classic champagne or Sable champagne: Classic and sable champagnes are difficult to distinguish without a DNA test. Grullos and classic champagnes are both dilutions of the black
Black (horse)
Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and novices frequently mistake dark chestnuts or bays for black. However, some breeds of horses, such as the Friesian horse, Murgese and Ariegeois are almost exclusively black...
coat, and typically have black or dark points and dove-gray coats. However, Grullos, in absence of any other dilution factors, are not born with pink skin and blue eyes, while champagnes always have these traits. As adults, grullos will retain their dark brown eyes and black skin, while champagnes have pinkish freckled skin and hazel eyes. Grullos, like all duns, will possess primitive markings
Primitive markings
Primitive markings among domestic horses are a group of hair coat markings and qualities associated with primitive breeds, and the dun coat color family in particular. All dun horses possess at least the dorsal stripe but the presence of the other primitive markings varies...
, and their coats are typically a cooler, slate shade, while classic and sable champagnes are chocolate-toned. The points and primitive markings on the grullo are black, while the points on classic and sable champagnes are brown. Grullos will have dun
Dun gene
The dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
ancestry and champagnes will have champagne ancestry.
Red dun vs. Dark gold champagne: Some gold champagnes have darker bodies and self-colored manes and tails. These horses may resemble red duns, however red duns have distinct primitive markings
Primitive markings
Primitive markings among domestic horses are a group of hair coat markings and qualities associated with primitive breeds, and the dun coat color family in particular. All dun horses possess at least the dorsal stripe but the presence of the other primitive markings varies...
and do not possess pinkish freckled skin or hazel eyes as adults, nor the bright pink skin and bright blue eyes of champagne foals.
Blue-eyed cream vs. Champagne: Blue-eyed cream is a collective term for any horse homozygous for the Cream gene
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
(cremello, perlino, etc.). Blue-eyed creams, as their name suggests, have blue eyes from birth through adulthood and also have pink skin. Typically their blue eyes are quite pale, and are easy to distinguish from the sky blue eyes of champagne foals and the hazel eyes of adult champagnes. Their skin may have a scant few black flecks, but the abundant freckles of champagne skin are absent. The respective shades of pink skin and blue eyes are slightly different.
Leopard vs. Champagne: The Leopard complex
Leopard complex
The leopard complex is a group of genetically-related coat patterns in horses. These patterns range from progressive increases in interspersed white hair similar to graying or roan to distinctive, Dalmatian-like leopard spots on a white coat. Secondary characteristics associated with the leopard...
is responsible for the spotted coat of the Appaloosa
Appaloosa
The Appaloosa is a horse breed best known for its colorful leopard-spotted coat pattern. There is a wide range of body types within the breed, stemming from the influence of multiple breeds of horses throughout its history. Each horse's color pattern is genetically the result of various spotting...
and other breeds. Even when a spotted hair coat is absent, other traits produced include mottled skin and a white sclera
Sclera
The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...
around the eye but generally the eye itself is dark brown. These mottles are alternations between unpigmented pink skin and pigmented skin, which is usually black (thus the mottles are black on a pink background). The mottles are substantially larger than the freckles of champagne skin, and leopard complex horses do not necessarily have light eyes.
Pearl vs. Champagne: In the homozygous state, or when combined with cream, the Pearl gene
Pearl gene
The Pearl gene, also known as the "Barlink factor," is a dilution gene that somewhat resembles the cream gene and the champagne gene, but is neither. It is a somewhat rare dilution gene found in the American Quarter Horse, American Paint Horse, and Peruvian Paso. The same mutation appears in...
produces a diluted apricot to buff color, pale eyes and pale skin. Heterozygous pearls (one copy of the gene) often exhibit dark skin with some pinkish freckles, while homozygous pearls (two copies of the gene) have champagne-like skin. The freckles on homozygous pearls and pearl-creams are pale and muted.
Prevalence
Compared to the cream gene, which is widespread throughout many breeds on different continents, the champagne gene is rare and found almost exclusively among American horse breeds. Nearly all American Cream DraftAmerican Cream Draft
The American Cream Draft is a rare draft horse breed, the only such breed developed in the United States that is still in existence. It is known for its cream color and amber eyes, produced by the champagne gene. The only other color found in the breed is chestnut, and the cream color produced by...
horses are gold champagne. The champagne gene is also found in the Tennessee Walking Horse, American Saddlebred
American Saddlebred
The American Saddlebred, formerly known as the American Saddle Horse, is a breed of horse that was developed in Kentucky by plantation owners. Today, in the horse show world, they are most commonly seen under saddle in Saddle seat style riding, and in various types of driving, including pleasure...
, Missouri Fox Trotter
Missouri Fox Trotter
The Missouri Fox Trotter is an American breed of horse with a unique four beat gait. It was bred in the Ozark Mountain foothills, and used by settlers who valued its smoothness.-Breed characteristics:...
, Racking horse
Racking horse
The Racking Horse is horse breed derived from the Tennessee Walking Horse, recognized by the USDA in 1978. It is known for a distinctive singlefoot gait. The breed has its own organization, the Racking Horse Breeders' Association of America, headquartered in Decatur, AL. Its goal is to...
, Kentucky Mountain Saddle Horse
Kentucky Mountain Saddle Horse
The Kentucky Mountain Saddle Horse is a gaited breed of horse developed in eastern Kentucky. They are a medium-sized horse used mainly for under-saddle work.- Characteristics :...
, Spanish Mustang
Spanish Mustang
The Spanish Mustang is a horse breed of historical importance. They descend from horses introduced from Spain during the early conquest of the Americas. They are a type that today is mostly or wholly now extinct in Spain...
, American Quarter Horse
American Quarter Horse
The American Quarter Horse is an American breed of horse that excels at sprinting short distances. Its name came from its ability to outdistance other breeds of horses in races of a quarter mile or less; some individuals have been clocked at speeds up to 55 mph...
, American Paint Horse
American Paint Horse
The American Paint Horse is a breed of horse that combines both the conformational characteristics of a western stock horse with a pinto spotting pattern of white and dark coat colors. Developed from a base of spotted horses with Quarter Horse and Thoroughbred bloodlines, the American Paint Horse...
, Appaloosa
Appaloosa
The Appaloosa is a horse breed best known for its colorful leopard-spotted coat pattern. There is a wide range of body types within the breed, stemming from the influence of multiple breeds of horses throughout its history. Each horse's color pattern is genetically the result of various spotting...
and Miniature horse
Miniature horse
Miniature horses are found in many nations, particularly in Europe and the Americas. The designation of miniature horse is determined by the height of the animal, which, depending on the particular breed registry involved, is usually less than as measured at the last hairs of the mane, which are...
breeds.
History
The champagne gene was located in 2008, but does not constitute a novel, or new, mutationMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
. It is widespread among American horses, and has likely been present in the genepool for more than a century. The Palomino
Palomino
Palomino is a coat color in horses, consisting of a gold coat and white mane and tail. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" base coat...
Horse Breeders Association (PHBA), which registers "palomino" horses based on appearance, includes allowances for freckle-skinned and hazel-eyed palominos. Furthermore, while the registry typically disallows horses with pink skin, it allows American Saddlebred
American Saddlebred
The American Saddlebred, formerly known as the American Saddle Horse, is a breed of horse that was developed in Kentucky by plantation owners. Today, in the horse show world, they are most commonly seen under saddle in Saddle seat style riding, and in various types of driving, including pleasure...
s with skin of any color to be registered. The PHBA was incorporated in 1941. Further back, the foundation mare of the American Cream Draft
American Cream Draft
The American Cream Draft is a rare draft horse breed, the only such breed developed in the United States that is still in existence. It is known for its cream color and amber eyes, produced by the champagne gene. The only other color found in the breed is chestnut, and the cream color produced by...
horse breed, "Old Granny", was born around 1905 in Iowa. Her cream-colored coat, pink skin and amber eyes are defining standards for the breed of her descendants, which are now known to be gold champagne.
The superficial similarities between gold champagne and palomino, and amber champagne and buckskin, may account for the relatively recent identification of champagne as a separate trait. Gold champagnes were sometimes called "pumpkin-skinned palomino." Classic champagnes, which lack the primitive markings
Primitive markings
Primitive markings among domestic horses are a group of hair coat markings and qualities associated with primitive breeds, and the dun coat color family in particular. All dun horses possess at least the dorsal stripe but the presence of the other primitive markings varies...
of true duns, were similarly called "lilac duns." The mare that brought the champagne coat color family to the attention of modern researchers was a Tennessee Walking Horse named "Champagne Lady Diane" born in 1969. A classic champagne, Champagne Lady Diane was described as "a genetic color accident" after her hairs were sent to several universities, although current evidence suggests that the champagne gene predates Champagne Lady Diane.
Locus (genetics)
In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...
.
Inheritance and expression
The champagne locusLocus (genetics)
In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...
is on exon
Exon
An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule either after portions of a precursor RNA have been removed by cis-splicing or when two or more precursor RNA molecules have been ligated by trans-splicing. The mature RNA molecule can be a messenger RNA...
2 of the SLC36A1
SLC36A1
Proton-coupled amino acid transporter 1 is a protein that in humans is encoded by the SLC36A1 gene.-Further reading:...
gene, which is on chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
14 (ECA14); a single nucleotide polymorphism
Single nucleotide polymorphism
A single-nucleotide polymorphism is a DNA sequence variation occurring when a single nucleotide — A, T, C or G — in the genome differs between members of a biological species or paired chromosomes in an individual...
(SNP) exchanges a C for a G at base 76 (c.188C>G) resulting in a missense mutation
Missense mutation
In genetics, a missense mutation is a point mutation in which a single nucleotide is changed, resulting in a codon that codes for a different amino acid . This can render the resulting protein nonfunctional...
. On a protein level, this SNP is predicted to result in the replacement of a threonine
Threonine
Threonine is an α-amino acid with the chemical formula HO2CCHCHCH3. Its codons are ACU, ACA, ACC, and ACG. This essential amino acid is classified as polar...
with arginine
Arginine
Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...
at amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
63 (T63R). SLC36A1 is not associated with pigmentation phenotypes in other species, and its role in most tissues is poorly understood. SLC36A1 is a member of a loosely-united group of over 300 proteins responsible for active transport
Active transport
Active transport is the movement of a substance against its concentration gradient . In all cells, this is usually concerned with accumulating high concentrations of molecules that the cell needs, such as ions, glucose, and amino acids. If the process uses chemical energy, such as from adenosine...
and facilitated diffusion
Facilitated diffusion
..Facilitated diffusion is a process of passive transport, facilitated by integral proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane integral proteins...
called the Solute carrier family
Solute carrier family
The solute carrier group of membrane transport proteins include over 300 members organized into 51 families. The SLC gene nomenclature system was originally proposed by the Human Genome Organization and is the basis for the official HUGO names of the genes that encode these transporters...
. Other members of this family include SLC45A2
SLC45A2
Membrane-associated transporter protein also known as solute carrier family 45 member 2 or melanoma antigen AIM1 is a protein that in humans is encoded by the SLC45A2 gene.-Function:...
, which is responsible for pigmentation variations of many types in humans, as well as the cream
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
coat color in horses; and SLC24A5
SLC24A5
Sodium/potassium/calcium exchanger 5 also known as solute carrier family 24 member 5 is a protein that in humans is encoded by the SLC24A5 gene that has a major influence on natural skin colour variation. The NCKX5 protein is a member of the potassium-dependent sodium/calcium exchanger family...
, which is responsible for the Golden dilution in mice
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...
.
Dilution gene
Dilution gene
Dilution gene is a popular term for any one of a number of genes that act to create a lighter coat color in living creatures. There are many examples of such genes:-General:...
s such as champagne and cream
Cream gene
The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
affect the nature or density of the pigments produced by melanocyte
Melanocyte
-External links: - "Eye: fovea, RPE" - "Integument: pigmented skin"...
s. On the other hand, genes in horses which produce white spotting, such as Frame
Lethal white syndrome
Lethal white syndrome , also called overo lethal white syndrome , lethal white overo , and overo lethal white foal syndrome , is an autosomal genetic disorder most prevalent in the American Paint Horse...
and Sabino1
Sabino horse
Sabino is a group of white spotting patterns in horses that affect the skin and hair. A wide variety of irregular color patterns are accepted as sabino. In the strictest sense, "sabino" refers to the white patterns produced by the Sabino 1 gene, for which there is a DNA test...
, interrupt or limit the migration of melanocyte
Melanocyte
-External links: - "Eye: fovea, RPE" - "Integument: pigmented skin"...
s from the neural crest
Neural crest
Neural crest cells are a transient, multipotent, migratory cell population unique to vertebrates that gives rise to a diverse cell lineage including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia....
. In other words, the skin, eyes, and hair of horses with the champagne mutation do not lack melanocytes, melanosomes, or melanins, but rather exhibit hypomelanism. However, the specific role of SLC36A1 in pigmentation and how the champagne coat colors are created on a molecular level is not known. The researchers who identified the mutation in 2008 suggested that melanosome
Melanosome
In a biological cell, a melanosome is an organelle containing melanin, the most common light-absorbing pigment found in the animal kingdom.Cells that synthesize melanins are called melanocytes, and also the retinal pigment epithelium cells, whereas cells that have merely engulfed the melanosomes...
pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
may be affected, which in turn might affect the processing of tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...
, a critical element of melanogenesis.
There are two alleles in this series: the recessive, wildtype allele ch and the dominant CH. The CH allele represents the T63R SLC36A1 mutation.
- ch/ch recessive homozygotesZygosityZygosity refers to the similarity of alleles for a trait in an organism. If both alleles are the same, the organism is homozygous for the trait. If both alleles are different, the organism is heterozygous for that trait...
are not affected by champagne and have no true champagne traits. - CH/ch heterozygotes have one champagne allele, and one wildtype non-champagne allele. The skin is bright pink and the eyes bright blue at birth, darkening to freckled and hazel with age, respectively. Both red and black pigment in the hair are diluted.
- CH/CH homozygotes (homozygous champagnes) have no wildtype non-champagne alleles. Such horses are indistinguishable from heterozygotes, except that their freckles may slightly sparser and the coat slightly lighter.
The DNA test for champagne detects the c.188C>G mutation on SLC36A1.
See also
- Cream geneCream geneThe cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay...
- Dilution geneDilution geneDilution gene is a popular term for any one of a number of genes that act to create a lighter coat color in living creatures. There are many examples of such genes:-General:...
- Dun geneDun geneThe dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene has the ability to affect the appearance of all black, bay, or chestnut -based horses to some degree by lightening the base body coat and suppressing the underlying base color to the...
- Equine coat colorEquine coat colorHorses exhibit a diverse array of coat colors and distinctive markings. A specialized vocabulary has evolved to describe them.While most horses remain the same color throughout life, a few, over the course of several years, will develop a different coat color from that with which they were born...
- Equine coat color geneticsEquine coat color geneticsEquine coat color genetics determine a horse's coat color. There are many different coat colors possible, but all colors are produced by the action of only a few different genes. The simplest genetic default color of all domesticated horses can be described as either "red" or "non-red", depending...
- Pearl genePearl geneThe Pearl gene, also known as the "Barlink factor," is a dilution gene that somewhat resembles the cream gene and the champagne gene, but is neither. It is a somewhat rare dilution gene found in the American Quarter Horse, American Paint Horse, and Peruvian Paso. The same mutation appears in...
- Silver dapple geneSilver dapple geneThe silver dapple gene is a dilution gene that affects the black base coat color. It will typically dilute a black mane and tail to flaxen, and a black body to a shade of brown or chocolate. It is responsible for a group of coat colors in horses called "silver dapple" in the west, or "taffy" in...