Dominant white or White spotting is a group of genetically related coat color conditions in the horse, best known for producing an all-white coat, but able to produce various forms of white spotting and white markings, several of which were or still are sometimes referred to as "sabino". There are many different forms of dominant white spotting; the white spotting produced can range from flashy white markings like those made by W20, to patterns similar to Sabino1, to a near white or white horse. Horses that are white are born with unpigmented pink skin and white hair with dark eyes. Under normal conditions, at least one parent must be dominant white to produce dominant white offspring. However, most of the currently-known alleles of dominant white can be linked to a documented spontaneous mutation in a single ancestor. For many of the W alleles, the white coats are, as the name suggests, inherited dominantly, meaning that a horse only needs one copy of the allele to have a white or white spotted coat.
Others, such as W20, are incompletely dominant, with horses with two copies having more white than horses with only one. In addition, different alleles which on their own give a white spotted but not white horse, such as W5 and W10, can combine to make a horse white. Dominant white can occur in any breed, has been studied in many different breeds. Two color breeds, the American White Horse and Camarillo White Horse, are characterized by their dominant white coats. Dominant white occurs on the same gene, KIT, as Sabino1. White is both visually distinct from gray and cremello. Dominant white is not the same as lethal white syndrome, nor are dominant white horses "albinos". Tyrosinase negative albinism has never been documented in horses; some forms of dominant white are thought to result in nonviable embryos when a zygote has two W alleles. However, such as W20, are viable in their homozygous form. Dominant white horses are born with pink skin and a white coat, which they retain throughout their lives.
Although the term "dominant white" is associated with a pure white coat, such horses may be all-white, near-white white, or exhibit an irregular spotting pattern similar to that of sabino horses. The amount of white hair depends on. Non-white areas of skin and hair are most seen along the dorsal midline of the horse, known as the topline, are common in the mane and on the ears, they may have interspersed specks or spots of non-white skin and hair. In addition, the hooves are most white, but may have striping if there is pigmented skin on the coronary band just above the hoof. In some cases, foals born with residual non-white hair may lose some or all of this pigment with age, without the help of the gray factor. Dominant white spotting is not known to affect eye color, most dominant white horses have brown eyes; the pink skin is devoid of pigment cells, appears pink from the underlying network of capillaries. White hair is rooted in unpigmented pink skin. There are many other genetic factors that produce white, near-white, off-white coat colors in horses, some of which are visually similar to dominant white.
White spotting from a W allele is difficult to identify visually, as it can range from small white markings in the case of a heterozygous W20 horse all the way to an obvious pinto pattern. In addition completely white horses can have genes which by themselves would only give white spotting, such as W20 combined with W22 or W5 combined with W10; as such, the only reliable way to find out whether a horse has one of the known white-spotting patterns from an allele on KIT is to have it genetically tested. Dominant white is one of several potential genetic causes for horses with near-white or white coats. To date, dominant white has been identified in multiple families of Thoroughbreds, American Quarter Horses, Frederiksborg horses, Icelandic horses, Shetland ponies, Franches Montagnes horses, South German Draft horses, in one family of the Arabian horse; the American White Horse, descended from one dominant white stallion crossed on non-white mares, is known for its dominant white coat, as is the Camarillo White Horse.
The W locus was mapped to the KIT gene in 2007. KIT is short for "KIT proto-oncogene receptor tyrosine kinase". White spotting is caused by alleles, of the KIT gene. All horses possess the KIT gene, as it is necessary for survival at the earliest stages of development; the presence or absence of dominant white is based on the presence of certain altered forms of KIT. Each unique form is called an allele, for every trait, all animals inherit one allele from each parent; the original or "normal" form of KIT, expected in horses without dominant white spotting, is called the "wild type" allele. Thus, a dominant white horse has at least one KIT allele with a mutation associated with dominant white spotting, either the wild type KIT allele or a second allele on KIT associated with white spotting, which could be one of the ones in the W series or could be Sabino1; the KIT gene contains over 2000 base pairs, a change in any of those base pairs results in a mutant allele. Over forty such alleles have been identified by sequencing the KIT genes of various horses.
The resultant phenotype of most of these alleles is not yet known, but 20 have been linked to dominant white. To date, DNA tests can identify if a horse carries the various identified W alleles
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 have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto patterns. Many breeds of horses carry pinto patterns. Pinto coloring, known as "coloured" in nations using British English, is the most popular in the United States. While pinto colored horses are not considered as a "breed," several competing color breed registries have formed to encourage the breeding of pinto colored horses; the word "paint" is sometimes used to describe pinto horses but today, it is used for the American Paint Horse. Pinto patterns are visually and genetically distinct from the leopard complex spotting patterns characteristic of horse breeds such as the Appaloosa. Breeders who select for color are careful not to cross the two patterns, registries that include spotting color preferences will refuse registration to horses that exhibit characteristics of the "wrong" pattern.
The word "pinto" is Spanish for'painted', also'dappled' or'spotted'. While pinto coloration has yet to be identified as a wildtype by DNA studies or seen in cave art predating horse domestication, images from pottery and other art of ancient antiquity show horses with flashy spotted patterns, indicating that they may have been desirable traits and selectively bred for. Images of spotted horses appear in the art of Ancient Egypt, archaeologists have found evidence of horses with spotted coat patterns on the Russian steppes before the rise of the Roman Empire. Spotted horses were among those brought to the Americas by the Conquistadors. By the 17th century in Europe, spotted horses were quite fashionable, though when the fad ended, large numbers of newly-unsellable horses were shipped to the Americas, some of which were sold while others were turned loose to run wild; the color became popular among Native Americans, was bred for in the United States, which now has the greatest number of pinto horses in the world.
There are a number of words which describe the various color and spotting patterns of pinto horses. A pinto horse is genetically created when an allele for a spotting pattern is present; the genes that create the underlying base coat color are not related to the genes that create white spotting. The precise mechanisms that create spotting are not all understood, but those that are known have human parallels, such as piebaldism. What horse terminology describes as "pinto" or "coloured" has been called leucism or "partial albinism" by pigment researchers. Common terms for describing different types of pinto horses include: Piebald:. Any pinto pattern on a black base coat, thus a black-and-white spotted horse. Skewbald:. Any pinto pattern on any base coat other than black; as chestnut and bay are the most common base coat colors, skewbalds are most chestnut and white or bay and white. At one time, the term may have applied more to brown-looking pinto horses, but today it encompasses any color other than black.
Coloured: The term for pinto coloration in nations using British English, including both piebald and skewbald. Tricolored or Tricoloured: a term for horse with three colors, in nations using British English, it is incorporated into the term skewbald. Tobiano: The most common type of pinto, tobiano is a spotting pattern characterized by rounded markings with white legs and white across the back between the withers and the dock of the tail arranged in a vertical pattern and more white than dark, though the ideal is a 50-50 distribution, with the head dark, having markings seen on a non-pinto horse. I.e. star, strip, or blaze. Tobiano is a simple dominant trait caused by a single gene and therefore all tobiano horses have at least one tobiano parent. A DNA test exists for tobiano. Tobiano is not associated with any health concerns. Overo: A collective term used by the American Paint Horse Association, overo means "pinto, but not tobiano." It denotes patterns produced by at least three different genetic mechanisms: frame, splashed white or sabino, described below.
These patterns are characterized by irregular markings with more jagged edges than tobiano markings. The white crosses the back. While some currently-identified overo patterns appear to be dominant or incomplete dominant traits, overo-patterned foals are produced from two solid-colored parents. Frame or frame overo: Frame is a popular and recognized type of non-tobiano pinto; this spotting pattern, in the absence of genes for other patterns, is characterized by horizontally-oriented white patches with jagged, crisp edges. White patches include the head and lateral aspects of the neck and body, the eyes can be blue. Frame overos may have modest markings that are not "pinto." This quality allows the pattern to "hide" for generations, is thought to be responsible for some cases of "cropouts." Frame is an incomplete dominant trait. However, foals born with two copies die shortly after birth. N/O frame horses do not have any known health defe
Black is a hair coat color of horses in which the entire hair coat is black. Black is a uncommon coat color, it is not uncommon to mistake dark chestnuts or bays for black. True black horses have dark brown eyes, black skin, wholly black hair coats without any areas of permanently reddish or brownish hair, they may have pink skin beneath any white markings under the areas of white hair, if such white markings include one or both eyes, the eyes may be blue. Many black horses "sun bleach" with exposure to the elements and sweat, therefore their coats may lose some of their rich black character and may resemble bay or seal brown, though examination of the color of hair around the eyes and genitals will determine color. Black horses that do not sun bleach are called "non-fading" blacks; some breeds of horses, such as the Friesian horse and Ariegeois are exclusively black. Black is common in the Fell pony, Dales pony and Alt-Oldenburger and Groningen; when identifying the base color of a horse, it is important to disregard all pink-skinned white markings.
White markings and patterns such as pinto and leopard have no bearing on the underlying base coat color of the animal. Black foals are born a mousy gray but can be darker shades; as many foals have primitive markings at birth, some black foals are mistaken for grullo or bay dun. Black foals have dark skin and eyes at birth. An adult-like black foal coat indicates that the foal will gray, if the foal has at least one gray parent. Graying can be confirmed by the presence of white hairs around muzzle. Gray Lipizzaner horses are born black. Black adult horses are easier to identify, as the coat must be black if superficially sun bleached. A sun bleached black may be confused with a dark bay, but a trained eye can distinguish between them by examining the fine hairs around the eyes and muzzle; when a black horse is sun-bleached, the mane and tail sun bleach most prominently, the rest of the coat may have a rusty tinge. A sun-bleached black may be mistaken for the less common smoky black, but can be distinguished by pedigree analysis or DNA testing.
Dark bay or seal brown: The darkest shades of bay are confused with black by experienced horse persons. However, a dark bay will always show some rich red character in its coat. Horses with a dark coat that may appear black, but have tan or reddish hairs around the eyes, muzzle and stifle are sometimes called "seal brown", "mahogany bay", or "black bay." Both colors can be confirmed with a DNA test. Liver chestnut: Some red horses are so dark that they appear black, are called "black chestnuts" as a consequence; however the darkest liver chestnuts will show some red character in their coats in the hair around the pastern or in the mane or tail. Dark liver chestnuts do not have any true black pigment in their coats; this can be verified with DNA testing. Liver chestnut is common in the Morgan horse. Smoky black: The action of the cream gene in the heterozygous condition has a minimal effect on black pigment, so heterozygous creams with a black base coat differ little from true blacks. A smoky black will have at least one cream parent, is born a pewter shade with blue eyes, retains reddish hair inside the ear through adulthood.
In the study and discussion of equine coat color genetics, black is considered a "base" color, as is red. This designation makes the effects of other coat color genes easier to understand. Coat colors that are designated "black-based" include grullo, smoky black, smoky cream, silver black, classic champagne, blue roan. Sometimes this designation includes the bay family: bay, seal brown, bay dun, silver bay, amber champagne, bay roan. Horses with a black-based coat may have added spotting patterns including leopard patterns seen on Appaloosas and the pinto coloring known as piebald; the genetics behind the black horse are simple. The color black is controlled by two genes: Extension and Agouti; the functional, dominant allele of the extension gene enables the horse to produce black pigment in the hair. Without this gene, the coat is devoid of black pigment and the horse is some shade of red; the functional, dominant allele of the agouti gene enable the horse to restrict black pigment to certain parts of the coat, notably the legs and tail, allowing the underlying red to show through, resulting in bay coloring.
Without this gene, any black pigment present is unrestricted. Thus a black horse has at least one copy of the functional, dominant "E" allele and two copies of the non-functional, recessive "a" allele. A mature true black horse can be safely said to possess at least one dominant extension gene. A DNA test, which uses hair with the root intact, has been developed to test for the Extension and Agouti genotypes. However, the terminology can be manipulated; the extension test is mislabeled as the "black test", leading to confusion. Neither the extension test nor the agouti test alone can identify a black horse. Together, they can determine that a horse that appears visually black is not a dark bay or liver chestnut. Horses described as "homozygous black" are homozyg
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 affected: any hairs that would have been red are gold, 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, 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 dilution. Champagne is not associated with any health defects. Other dilution genes in horses include 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 palominos, buckskins, or grullos, 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 the American Cream Draft, Tennessee Walker, American Saddlebred and Missouri Fox Trotter. Champagne is a dominant trait, based on a mutation in the SLC36A1 gene. A horse with either one or two champagne genes 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 carry other coat color genes that affect their phenotype, or outward color.
Horses with the champagne gene have 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; 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 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 the mane and tail a darker shade; the legs may be darker. The overall effect has been described as lilac, dark taupe, green; this color is most misclassified as grullo, 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, can be confirmed by a DNA test negative for the recessive black allele at Agouti. 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 lighter than the mane and tail, the colored points may be difficult to see. The mane and tail may have "frosting" or light edges, a trait that occurs in bay duns and some buckskins. Amber champagne can be confused with bay dun. Gold champagne is produced by the action of champagne on a chestnut coat; the coat is gold, the mane and tail are ivory. In some cases, the mane and tail may be self-colored; these gold champagnes may be an all-over apricot shade. Dark gold champagnes can be confused with red dun, while those with paler manes and tails were called "pumpkin-skinned palominos."
Apart from the unique shades, there are several qualities of the champagne coat that may be used to help identify them. Champagne coats have an unusual sheen; this sheen makes champagnes difficult to photograph as the appearance of the coat depends on the lighting. Not all champagne horses have this sheen, there are many shiny non-champagne horses, so a "sheen" in and of itself does not indicate the champagne gene; the coat may exhibit reverse dappling, though this is 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, specks, or blotches - are dark and may have a purple cast, 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, exhibit a scant few tiny black specks.
Homozygous pearls and pearl-cream combinations 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 qualiti
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. Most white markings are present at birth, the underlying skin color of a horse does not change, absent disease; the basic outline of equine coat color genetics has been resolved, DNA tests to determine the likelihood that a horse will have offspring of a given color have been developed for some colors. Discussion and controversy continues about some of the details those surrounding spotting patterns, color sub-shades such as "sooty" or "flaxen", markings. Genetically, all horses start out as either chestnut, called "red" by geneticists, represented by the absence of the extension gene; therefore and black are the two base colors. The Bay color is expressed when the Agouti gene, works on black; the vast range of all other coat colors are created by additional genes' action upon one of these three coat colors.
Statistically, the most seen horse color phenotypes are identified by the following terms: Bay: Body color ranges from a light reddish-brown to dark brown with "black points". The main color variations are: Dark bay: dark red or brown hair, difficult to distinguish from seal brown. Sometimes called "black bay", "mahogany bay", or "brown". Blood bay: bright red hair. Brown: The word "brown" is used by some breed registries to describe dark bays. There is a distinct allele that darkens a bay coat to seal brown, but it is not the cause of all forms of dark bay. Informally, "brown" is applied to many distinct coat colors. Most horses described by casual observers as "brown" are bay or chestnut. In the absence of DNA testing and bay can be distinguished from each other by looking at the mane and legs for the presence of black points. Chestnut: A reddish body color with no black. Mane and tail are the same lighter than the body coat; the main color variations are: Liver chestnut: dark brown coat. Sometimes a liver chestnut is 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. 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. Most will gray out to either a complete white or to a "fleabitten" coat, which retains speckles of the horses original colour. Most "white" horses are grays with a white hair coat. A gray horse is distinguished from a white horse by dark skin noticeable around the eyes, muzzle and other areas of thin or no hair. Variations of gray that 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 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". Black: Black is uncommon, though it is not "rare". There are two types of fading black and non-fading black. Most black horses will fade to a brownish color. Non-fading black is a blue-black shade. Genetically, the two cannot yet be differentiated, some claim the difference occurs due to management rather than genetics, though this claim is hotly disputed. Most black foals are 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 black except for white markings. A sun-bleached black horse is still black 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. Brindle: One of the rarest colors in horses linked to chimerism.
Characteristics are any color with "zebra-like" stripes, but most common is a brown horse with faint yellowish markings. A heritable brindle pattern in a family of American Quarter Horses, named Brindle1 was identified and announced in late 2016. 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. 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 confused with palomino, dun, or buckskins. Cream dilution, an incomplete dominant gene that produces a diluted coat color with one copy of the allele and a full dilution with two copies. Colors produced include Palomino, Perlino and Smoky Cream or Smoky black. Cremello: A horse with a chestnut base coat and two cream genes that wash out all color until
Seal brown (horse)
Seal brown is a hair coat color of horses characterized by a near-black body color. The term is not to be confused with "brown", used by some breed registries to refer to either a seal brown horse or to a dark bay without the additional characteristics of seal brown genetics. Like bay, the seal brown color is produced by the Agouti gene acting upon a genetically black base coat, suppressing the black into point coloration and allowing the underlying reddish or brownish color to appear; however seal brown is designated with the qualifier At The genetic study of seal brown is new. Several theories were advanced in the last century to explain the heredity of the seal brown coat, while a DNA test said to detect the seal brown allele was developed, the test was never subjected to peer review and due to unreliable results was subsequently pulled from the market; the genetically and visually related dark bay coat color, which features black points and a near-black body, differs from true seal brown in the absence of tan markings.
The term "seal brown" is to be distinguished from the term "brown." Another mimic is the liver chestnut, an all-over dark brown coat including mane and tail, sometimes confused with seal brown. However, true seal browns have black points characteristic of all bay horses, while liver chestnuts do not; the research behind the classification of seal brown as distinct from dark bay is quite new, as a result, opinions vary on what constitutes a true seal brown. In Equine Color Genetics, Dan Phillip Sponenberg wrote "In general, all dark colors with black points that are lighter than black but darker than bay are called brown." In this text, he classifies black-pointed, clear reddish coats of any shade as bay, black-pointed coats of any shade with black countershading as brown. These definitions, while precise, are no longer accurate in light of current research. True seal brown is best described as a black or nearly-black coat with reddish or tan hairs on the "soft parts": the muzzle, inner ears, behind the elbow, in front of the stifle.
Like other coat colors, seal browns can range in shade. The darkest are just about black except for their tan areas. Lighter examples are confused with dark bays; the mane and legs are always black. Non-horse people refer to many horse coat colors as "brown," in particular the bay color. Among horse aficionados, a common assessment is that "... is only used by people with one horse or with two hundred." The implication is that lay observers will refer to a horse's coat color to be "brown" due to a lack of vocabulary, those discussing large populations of horses will use "brown" out of a need for a more specific vocabulary. The term "seal brown" is unlikely to be part of a novice's repertoire and is therefore preferable when discussing this specific coat color; this coat color is, called "black and tan" in some languages. In the most simple terms, the vast majority of horses are indeed some shade of brown, but not "seal brown." Such coat colors include: Chestnut copper-red to liver-brown, without true black hair.
Bay, reddish-brown to quite dark-brown body coat with true black mane and legs. Both bay and chestnut may be darkened by the sooty gene. Buckskin, tan or gold body coat with the black areas of a bay. Dun tan with evident primitive markings. Silver dapples, sometimes called "chocolate", are found in brownish shades. Not all breed registries or studbooks recognize seal brown as a distinct coat color; the American Quarter Horse Association and American Paint Horse Association both recognize "brown" as a separate category, while the Arabian Horse Association labels all non-black, black-pointed shades "bay."Still other registries, such as The Jockey Club which registers Thoroughbreds and Appaloosa Horse Club, offer the designation "dark bay or brown" to cope with the ambiguity in terminology and identification. Among German breeds and registries, the term rappe indicates a black horse, braun is bay, while dunkelbraun indicates dark bay and schwarzbraun indicates seal brown. In France, seal brown horses are recognized among the "black coat family".
The presence of other coat color genes can modify a seal brown coat. The seal brown family includes: Brown Buckskin, is a result of the dilution effect of a single copy of the cream gene. Sometimes called smoky brown; the black areas of the seal brown coat are unaffected or lightened, while the reddish areas are more golden, may have lighter eyes. Brown buckskins are quite hard to distinguish from seal browns. Sable champagne, a result of the dilution effect of the champagne gene. Like all champagnes, sable champagnes have pinkish, freckled skin; the coat is a flat, diluted grayish- or purplish-brown, somewhere between the warm pumpkin tones of the bay-based amber champagne, the cool purplish tones of the black-based classic champagne. Brown dun, a result of the dilution effect of the dun gene. Like all duns, brown duns have conspicuous primitive markings including at least a dorsal stripe and darker points; the primitive markings of brown duns are black, the coat color is somewhere between the slate gray of a grulla and the peanut butter of a bay dun.
The appearance of a horse's skin and coat-color is determined by pigment chemicals called melanins. Two types of melanins are used by mammals, such as horses and humans: eumelanin, visually black to brown, phaeomelanin
Dog breeds are dogs that have uniform physical characteristics developed by humans, with breeding animals selected for phenotypic traits such as size, coat color and behavior. The Fédération Cynologique Internationale recognizes 337 pure dog breeds. Other uses of the term breed when referring to dogs may include pure breeds, cross-breeds, mixed breeds and natural breeds; the domestic dog is the first species, the only large carnivore, to have been domesticated. Over the past 200 years, dogs have undergone rapid phenotypic change and were formed into today's modern breeds due to artificial selection imposed by humans; these breeds can vary in weight from a 0.46 kg teacup poodle to a 90 kg giant mastiff. The skull and limb proportions vary between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores; some breeds demonstrate outstanding skills in herding, scent detection, guarding, which demonstrates the functional and behavioral diversity of dogs.
The first dogs were wolflike, but the phenotypic changes that coincided with the dog–wolf genetic divergence are not known. In 2017, a study showed that 9,000 years ago the domestic dog was present at what is now Zhokhov Island, arctic north-eastern Siberia, connected to the mainland at that time; the dogs were selectively bred as either sled dogs or as hunting dogs, which implies that a sled dog standard and a hunting dog standard existed at that time. The optimal maximum size for a sled dog is 20–25 kg based on thermo-regulation, the ancient sled dogs were between 16–25 kg; the same standard has been found in the remains of sled dogs from this region 2,000 ago and in the modern Siberian Husky breed standard. Other dogs were more massive at 30 kg and appear to be dogs, crossed with wolves and used for polar-bear hunting. At death, the heads of the dogs had been separated from their bodies by humans for ceremonial reasons. Between 3,000 and 4,000 years ago greyhound-type dogs were depicted on pottery and paintings in Egypt and Western Asia.
Mastiff-type dogs were kept for guarding and hunting, short-legged dogs were bred. Most modern dog breeds are the products of the controlled breeding practices of the Victorian era, the accurate documenting of pedigrees with the establishment of the English Kennel Club in 1873 in imitation of other stud book registries for cattle and horses. For early depictions of dogs in art, see early history in art. Ancient breed of dogs was a term once used for a group of dog breeds by the American Kennel Club, but no longer; these breeds were referred to as "ancient breeds", as opposed to modern breeds because it was believed that they had origins dating back over 500 years. In 2004, a study looked at the microsatellites of 414 purebred dogs representing 85 breeds; the study found that dog breeds were so genetically distinct that 99% of individual dogs could be assigned to their breed based on their genotype, indicating that breeding barriers has led to distinct genetic units. The study identified 9 breeds that could be represented on the branches of a phylogenetic tree which grouped together with strong statistical support and could be separated from the other breeds with a modern European origin.
These 9 breeds had been referred to as opposed to the modern breeds. The study found that the Pharaoh Hound and Ibizan Hound were not as old as believed but had been recreated from combinations of other breeds, that the Norwegian Elkhound grouped with the other European dogs despite reports of direct Scandinavian origins dating back 5,000 years; the dog which accompanied the ancestors of Native Americans from Siberia is extinct. See further: Dog typeThe spread of modern dog breeds has been difficult to resolve because many are the products of the controlled breeding practices of the Victorian era. In 2010, a study looked at 48,000 single nucleotide polymorphisms that gave a genome-wide coverage of 912 dogs representing 85 breeds; the study found distinct genetic clusters within modern dogs that corresponded to phenotype or function. These included spitz-breeds, toy dogs, Mastiff-like breeds, small terriers, herding dogs, scent-hounds, sight-hounds. There were 17 breeds that conflicted with phenotype or function and these were thought to be the result of crossing some of the other phenotypes.
As in a 2004 study that found 9 ‘ancient breeds’ to be genetically divergent, the study found 13 breeds that were genetically divergent from the modern breeds: the Basenji, Afghan hound, Canaan dog, New Guinea singing dog, Chow Chow, Chinese Shar Pei, Alaskan malamute, Siberian husky and American Eskimo dog. Results indicated that the Basenji had recent admixture with Middle Eastern wolves; the study found that there were three well-supported groups that were divergent and distinct from modern domestic dogs. The three groups were an Asian group that showed past admixture with Chinese wolves, a Middle Eastern group, a northern group. In 2012, a study looked at 49,000 Single nucleotide polymorphisms that gave a genome-wide coverage of 1,375 dogs representing 35 breeds, 19 wolves, previous published genetic signatures of other breeds, giving a total of 121 breeds covered; the study found a deep genetic split between old-world and new-world wolves, confirmed the genetic divergence of 13 breeds from a 2010 study (Afghan Hound, Alaskan Malamute, American Eskimo, Canaan dog, Chow Chow, D