Primitive markings

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Przewalski's horse is thought to be similar in appearance to ancestors of today's domestic horses. Przewalskipferd cologne.jpg
Przewalski's horse is thought to be similar in appearance to ancestors of today's domestic horses.

Primitive markings are a group of hair coat markings and qualities seen in several equine species, including horses, donkeys, and asses. In horses, they are associated with primitive breeds, [1] though not limited to such breeds. The markings are particularly associated with the dun coat color family. [2] All dun horses possess at least the dorsal stripe, [1] [2] [3] but the presence of the other primitive markings varies. Other common markings may include horizontal striping on the legs, transverse striping across the shoulders, and lighter guard hairs along the edges of a dark mane and tail.

Contents

Origin

A cave painting of a wild horse, Lascaux Lascaux2.jpg
A cave painting of a wild horse, Lascaux

The dun coat and attendant primitive or "dun factor" markings reflect the wild type coat and are observed in all equine species. [3] Some cave paintings depict horses as being dun and with the primitive markings. The Przewalski's horse is dun-colored with primitive markings. So, too, are horse breeds such as the Konik and the Heck horse, "bred back" to resemble the now-extinct tarpan, many of which are grullo or mouse dun in color.

Every dun horse has a dorsal stripe, and some dun horses also have additional primitive markings. Some non-dun horses may also show primitive markings, namely newborn foals and horses with the non-dun 1 gene. [1] [4] Primitive markings in horses are an example of atavism: preservation of or reversion to ancestral type. While primitive markings are closely linked with the dun coat colors, the variations of expression and presence in non-dun horses suggest that the markings themselves may be governed by a separate genetic mechanism. [1] [5]

Dorsal stripe

Kiangs have bold dorsal stripes. Equus kiang holdereri02.jpg
Kiangs have bold dorsal stripes.

Of equids other than horses, all except the mountain zebra show a distinct dorsal stripe. Among domesticated donkeys, most have a black dorsal stripe, though it can be difficult to see on melanistic individuals. [5] In the African wild ass, the dorsal stripe is thin but distinct and black. In Przewalski's horse, the dorsal stripe is usually dark brown, while it is black in the bred-back tarpan. In the plains zebra, the dorsal stripe is narrow and edged by white, while in Grevy's zebra, it is quite bold. The dorsal stripes of the onager and kiang are dark brown and especially vivid.

The dorsal stripe reflects the original coat color of the horse. Those on bay duns may be black or reddish, [5] while those on red duns are distinctly red. Dorsal stripes on dun horses with the cream gene seem unaffected by cream: smoky black-duns ("smoky grullas"), buckskin-duns ("dunskins"), and palomino-duns ("dunalinos") have black, brown, or red dorsal stripes, as well.

Leg bars and markings

Leg bars and "zippers": This horse's legs have been shaved. Stipe-leg-pattern-on-domestic-horse-IMG 0214.jpg
Leg bars and "zippers": This horse's legs have been shaved.

Also called zebra bars, tiger stripes, [6] or garters, leg bars are the most common accessory to the dorsal stripe. [1] Leg bars are most commonly seen on or above the knees and hocks, and reflect the underlying coat color. Leg bars on bay duns are black within the points, and reddish above them. [7]

Leg bars are prominent on Grevy's zebras and mountain zebras, and African wild asses also have well-defined black leg bars below the forearm and gaskin on a white or pale background. However, as in horses, expression of leg bars seems to vary widely among donkeys, plains zebras, and Przewalski's horses, while they appear very seldom or not at all in onagers and kiangs.

Leg markings may also take the form of blotches, patches, marbling, mottling, or spotting. [1]

One classical genetics study concluded that stripes on the front legs seem to follow an autosomal dominant mode of inheritance. [8]

Shoulder stripe

Transverse shoulder stripes are common on asses. Equus asinus - Ufenau 2011-07-25 17-32-24.jpg
Transverse shoulder stripes are common on asses.

The shoulder stripe is a transverse or "vertical" marking that usually crosses the withers and extends down the shoulders. [1] [6] [7] Donkeys are known for their distinct shoulder stripe, which, when combined with the dorsal stripe, is sometimes called a "cross". It is more marked in breeds closest to the wild African ancestors of the domestic donkey. [9] Indistinct or poorly defined markings in these regions are often called neck or shoulder smudges, patches, or shadows. Especially large markings are called neck or shoulder capes. [7] The kiang exhibits some shoulder smudging.

Head markings

This Konik shows the dark face mask and frosted mane common to primitive horses. Koniks5.JPG
This Konik shows the dark face mask and frosted mane common to primitive horses.

Many primitive markings may occur on the animal's head.

Guard hairs

The long-roached manes of Fjords clearly show the light, outside primitive guard hairs. Fjordpferd - Kopf.jpg
The long-roached manes of Fjords clearly show the light, outside primitive guard hairs.

The dorsal stripe runs through the mane and tail of a dun horse, so the center of the mane and tail are darker. The outer edges may be significantly lighter, even close to white. These paler hairs are seen at the base of the tail and on the edges of the mane. The presence of guard hairs may also be called "frosting". [7] Such characteristics are very visible among the Fjord horses, which have their sandwich-patterned manes shaved short and upright. The presence of paler guard hairs on the mane and tail is seen throughout Equus .

Other markings

Dorsal stripe and pale guard hairs on the dock of a domestic horse Dorsal stripe on a domestic horse IMG 0233.jpg
Dorsal stripe and pale guard hairs on the dock of a domestic horse

Less common primitive markings include vertically oriented markings which may be arranged as bars, fine striping, or smudges. Such markings include:

Primitive markings in non-dun horses

This horse's dorsal stripe is most likely caused by non-dun 1. Countershading stripe.jpg
This horse's dorsal stripe is most likely caused by non-dun 1.

Less distinct primitive markings can also occur on non-dun horses, even in breeds which are not known to have any dun individuals. The most common primitive marking found is a dorsal stripe. [1] Most non-dun horses do not have darker primitive markings, but some do. This is because there are two types of non-dun, called non-dun1 and non-dun2. Non-dun 1 removes the diluting effect of dun, but keeps the primitive markings, while non-dun 2 removes both the diluting effect and the primitive markings. [13] The non-dun1 allele is over 40,000 years old, while non-dun2 is relatively recent, and is thought to have first appeared within the past several thousand years. [4] Primitive markings on non-duns can be seasonal, visible only when the horse is shedding its coat. [14]

Dorsal stripes and other primitive markings on non-dun horses used to be called "countershading" dorsals [5] before their genetic cause was discovered at the dun locus. [4] This is not to be confused with the camouflage mechanism of countershading.

Primitive markings in foals

Many foals, particularly if they are buckskin, smoky black, or black, are born with primitive markings such as dorsal stripes and leg bars that disappear after the foal coat sheds. Such horses are sometimes mistakenly registered as dun. This error seems particularly common in foals that turn gray. [5]

See also

Related Research Articles

<span class="mw-page-title-main">Palomino</span> Genetic color in horses

Palomino is a genetic color in horses, consisting of a gold coat and white mane and tail; the degree of whiteness can vary from bright white to yellow. The palomino color derived from the inter-breeding of Spanish horses with those from the United States. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" (chestnut) base coat. Palomino is created by a genetic mechanism of incomplete dominance, hence it is not considered true-breeding. However, most color breed registries that record palomino horses were founded before equine coat color genetics were understood as well as they are today, therefore the standard definition of a palomino is based on the visible coat color, not heritability nor the underlying presence of the dilution gene.

<span class="mw-page-title-main">Tarpan</span> Extinct subspecies of equines

The tarpan was a free-ranging horse subspecies of the Eurasian steppe from the 18th to the 20th century. It is generally unknown whether those horses represented genuine wild horses, feral domestic horses or hybrids. The last individual believed to be a tarpan died in captivity in the Russian Empire in 1909.

<span class="mw-page-title-main">Bay (horse)</span> Hair coat color of horses

Bay is a hair coat color of horses, characterized by a reddish-brown or brown body color with a black point coloration on the mane, tail, ear edges, and lower legs. Bay is one of the most common coat colors in many horse breeds.

<span class="mw-page-title-main">Buckskin (horse)</span> Equine coat color

Buckskin is a colour of horse. Buckskins coloring is a hair coat color referring to a color that resembles certain shades of tanned deerskin. Similar colors in some breeds of dogs are also called buckskin. The horse has a tan or gold colored coat with black points. Buckskin occurs as a result of the cream dilution gene acting on a bay horse. Therefore, a buckskin has the Extension, or "black base coat" (E) gene, the agouti gene (A) gene, which restricts the black base coat to the points, and one copy of the cream gene (CCr), which lightens the red/brown color of the bay coat to a tan/gold.

<i>Equus</i> (genus) Genus of mammals which includes horses, donkeys, and zebras

Equus is a genus of mammals in the family Equidae, which includes horses, asses, and zebras. Within the Equidae, Equus is the only recognized extant genus, comprising seven living species. Like Equidae more broadly, Equus has numerous extinct species known only from fossils. The genus most likely originated in North America and spread quickly to the Old World. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes, and long tails. All species are herbivorous, and mostly grazers, with simpler digestive systems than ruminants but able to subsist on lower-quality vegetation.

<span class="mw-page-title-main">Brindle</span> Coat coloring pattern in some animals

Brindle is a coat coloring pattern in animals, particularly dogs, cattle, guinea pigs, cats, and, rarely, horses. It is sometimes described as "tiger-striped", although the brindle pattern is more subtle than that of a tiger's coat.

<span class="mw-page-title-main">Point coloration</span> Coloration of animal coat/fur

Point coloration is animal coat coloration with a pale body and relatively darker extremities, i.e. the face, ears, feet, tail, and scrotum. It is most recognized as the coloration of Siamese and related breeds of cat, but can be found in dogs, rabbits, rats, sheep, guinea pigs and horses as well.

<span class="mw-page-title-main">Cream gene</span> Gene for several horse coat colors

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 base coat and the cream gene will be buckskin or perlino. A black base coat with the cream gene becomes the not-always-recognized smoky black or a smoky cream. Cream horses, even those with blue eyes, are not white horses. Dilution coloring is also not related to any of the white spotting patterns.

<span class="mw-page-title-main">Champagne gene</span> Simple dominant allele responsible for a number of rare horse coat colors

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.

<span class="mw-page-title-main">Equine coat color genetics</span> Genetics behind the equine coat color

Equine coat color genetics determine a horse's coat color. Many colors are possible, but all variations are produced by changes in only a few genes. Bay is the most common color of horse, followed by black and chestnut. A change at the agouti locus is capable of turning bay to black, while a mutation at the extension locus can turn bay or black to chestnut.

<span class="mw-page-title-main">Dun gene</span> Dilution 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 lightens most of the body while leaving the mane, tail, legs, and primitive markings the shade of the undiluted base coat color. A dun horse always has a dark dorsal stripe down the middle of its back, usually has a darker face and legs, and may have transverse striping across the shoulders or horizontal striping on the back of the forelegs. Body color depends on the underlying coat color genetics. A classic "bay dun" is a gray-gold or tan, characterized by a body color ranging from sandy yellow to reddish brown. Duns with a chestnut base may appear a light tan shade, and those with black base coloration are a smoky gray. Manes, tails, primitive markings, and other dark areas are usually the shade of the undiluted base coat color. The dun gene may interact with all other coat color alleles.

<span class="mw-page-title-main">Sorraia</span> Breed of horse

The Sorraia is a rare breed of horse indigenous to the portion of the Iberian peninsula, in the Sorraia River basin, in Portugal. The Sorraia is known for its primitive features, including a convex profile and dun coloring with primitive markings. Concerning its origins, a theory has been advanced by some authors that the Sorraia is a descendant of primitive horses belonging to the naturally occurring wild fauna of Southern Iberia. Studies are currently ongoing to discover the relationship between the Sorraia and various wild horse types, as well as its relationship with other breeds from the Iberian Peninsula and Northern Africa.

<span class="mw-page-title-main">Fjord horse</span> Breed of horse

The Fjord or Norwegian Fjord Horse is a relatively small but very strong horse breed from the mountainous regions of western Norway. It is an agile breed of light draught horse build. It is always dun in colour, with five variations in shade recognised in the breed standard. One of the world's oldest breeds, it has been used for hundreds of years as a farm horse in Norway, and in modern times is popular for its generally good temperament. It is used both as a harness horse and under saddle.

<span class="mw-page-title-main">Grullo</span> Color of horses in the dun family

Grullo or grulla 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. The genotype for grulla horses is a black base with dun dilution. In this coloration, each individual hair is mouse-colored, unlike a roan, which is composed of a mixture of dark and light hairs. The several shades of grulla are informally referred to with a variety of terms, including black dun, blue dun, slate grulla, silver grulla or light grulla, silver dun, or lobo dun. Silver grulla may also refer to a grulla horse with silver dapple, regardless of shade.

<span class="mw-page-title-main">Chestnut (horse color)</span> Horse coat color

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. Chestnut is characterized by the absolute absence of true black hairs. It is one of the most common horse coat colors, seen in almost every breed of horse.

<span class="mw-page-title-main">Equine coat color</span> Horse coat colors and markings

Horses exhibit a diverse array of coat colors and distinctive markings. A specialized vocabulary has evolved to describe them.

<span class="mw-page-title-main">Black horse</span> Horse coat color

Black is a hair coat color of horses in which the entire hair coat is black. It is not uncommon to mistake dark chestnuts or bays for black.

<span class="mw-page-title-main">Horse markings</span> Colored areas, usually white, on a horse that differ from the body color

Markings on horses are usually 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. Most markings have pink skin underneath most of the white hairs, though a few faint markings may occasionally have white hair with no underlying pink skin. Markings may appear to change slightly when a horse grows or sheds its winter coat, however this difference is simply a factor of hair coat length; the underlying pattern does not change.

<span class="mw-page-title-main">Sooty horse</span> Trait characterized by black or darker hairs mixed into a horses coat

A sooty or smutty horse coat color is characterized by black or darker hairs mixed into a horse's coat, typically concentrated along the topline of the horse and less prevalent on the underparts. The effect is especially pronounced on buckskins and palominos. Sootiness is believed to be an inherited trait involving multiple genes, however the details are not yet known. Horses without any visible sooty coloration are termed "clear-coated."

<span class="mw-page-title-main">Seal brown (horse)</span> Hair coat color of horses

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. The term is not to be confused with "brown", which is 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.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Stachurska, AM (1999). "Inheritance of primitive markings in horses". Journal of Animal Breeding and Genetics. 116: 29–38. doi:10.1111/j.1439-0388.1999.00172.x.
  2. 1 2 "Dun Zygosity Test". UC Davis. Retrieved 2008-06-20.
  3. 1 2 Lusis, JA (1943). "Striping patterns in domestic horses". Genetica. 23 (1): 31–62. doi:10.1007/BF01763802. S2CID   19047145.
  4. 1 2 3 Imsland F, McGowan K, Rubin CJ, Henegar C, Sundström E, Berglund J, et al. (February 2016). "Regulatory mutations in TBX3 disrupt asymmetric hair pigmentation that underlies Dun camouflage color in horses". Nature Genetics. 48 (2): 152–8. doi:10.1038/ng.3475. PMC   4731265 . PMID   26691985.
  5. 1 2 3 4 5 6 7 Castle, Nancy (2008). "Primitive Marking Theory" (PDF). Dun Central Station. Archived from the original (PDF) on May 16, 2008. Retrieved 2008-06-20.
  6. 1 2 "Dun". Equine Color. Archived from the original on 2008-05-25. Retrieved 2008-06-20.
  7. 1 2 3 4 5 6 7 8 "Adult Markings". Dun Central Station. Archived from the original on October 14, 2008. Retrieved 2008-06-20.
  8. Stachurska, A. M. (1999). "Inheritance of Primitive Markings in Horses". Journal of Animal Breeding and Genetics. 116: 29–38. doi:10.1111/j.1439-0388.1999.00172.x.
  9. Roger Blench (2013). Wild asses and donkeys in Africa: interdisciplinary evidence for their biogeography, history and current use. Paper presented at the School of Oriental and African Studies, London, 9 May 2012 (revised version, 2013). Accessed July 2014.
  10. 1 2 "Definitions". Dungenes. Archived from the original on 2011-07-26. Retrieved 2010-12-02.
  11. "Grulla". Dun Central Station. Archived from the original on April 11, 2008. Retrieved 2008-06-26. "Zippers" on the backs of the fetlocks of dun dilute colored horses is a common sight. When clipped, the light line running up the back of the fetlock will be very crisp.
  12. Mioko MASUDA; Junko TSUNODA; Hiroko NOMURA; Nami KIMURA; Gombojav ALTANGEREL; Bandi NAMKHAI; Usukhjargal DOLJ; Michinari YOKOHAMA (2007). "New Primitive Marking (Bider) in Mongolian Native Horse and Equus przewalskii". Journal of Equine Science. 18 (4): 145–151. doi: 10.1294/jes.18.145 . Retrieved 2008-12-19.
  13. "More about Dun and Primitive Markings". Etalon Diagnostics. Retrieved 2019-04-28.
  14. Nancy Castle. "Look-A-Like Collages". Dun Look-A-Likes. Dun Central Station. Archived from the original on October 12, 2008. Retrieved 2008-06-26.