Black horse
This article includes a improve this article by introducing more precise citations. (October 2016) ) |
Black | |
---|---|
Variants | Fading, non-fading, possibly genetic |
Genotype | |
Base color | Extension "E" |
Modifying genes | none |
Description | Solid black base color uniform over entire body other than markings |
Skin | Black |
Eyes | Brown |
Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and it is not uncommon to mistake dark chestnuts or bays for black.
True black horses have dark brown eyes, black skin, and 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, and 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, and therefore their coats may lose some of their rich black character and may even resemble bay or seal brown, though examination of the color of hair around the eyes, muzzle and genitals often will determine color. Black horses that do not sun bleach are called "true" blacks.
Some
Visual identification
When identifying the base color of a horse, it is important to disregard all pink-skinned white
Black
Black adult horses are easier to identify, as the coat must be entirely black, even if superficially sun bleached. A sun bleached black may be confused with a dark bay, but a trained eye can distinguish between them, particularly by examining the fine hairs around the eyes and muzzle. When a black horse is sun-bleached, the mane and tail often sun bleach most prominently, and the rest of the coat may have a rusty tinge. A sun-bleached black may also be mistaken for the less common smoky black, but can be distinguished by pedigree analysis or DNA testing.
Black mimics
- Dark bay or seal brown: The darkest shades of bay are commonly confused with black, even by experienced horse persons. However, a dark bay will always show some rich red character in its coat. Horses with a very dark coat that may appear black, but have tan or reddish hairs around the eyes, muzzle, armpits, and stifle are sometimes called "seal brown", "mahogany bay", or "black bay." Both colors are genetically distinct from black and can be confirmed with a DNA test.
- Liver chestnut: Some red horses are so dark that they appear black, and are often called "black chestnuts" as a consequence. However, even the darkest liver chestnuts will show some red character in their coats, usually in the hair around the pastern or in the mane or tail. Even dark liver chestnuts do not have any true black pigment in their coats. This can be verified with DNA testing. Liver chestnut is very common in the Morgan horse.
- heterozygouscondition has a minimal effect on black pigment, so heterozygous creams with a black base coat (smoky blacks) differ little from true blacks. A smoky black will have at least one cream parent, is often born a pewter shade with blue eyes, and usually retains reddish hair inside the ear through adulthood.
Genetic identification
In the study and discussion of
.The genetics behind the black horse are relatively simple. The color black is primarily controlled by two genes:
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 (EE or Ee); and has no other dominant genes (such as agouti, gray, or any of the dilution factors) that further modify color.
A
Horses described as "homozygous black" are simply homozygous for the dominant extension gene (EE); they are homozygous "not-red". Such horses are only "guaranteed" to never produce a
However, it has become popular for individuals owning a horse that is homozygous for the extension gene (EE) to claim that the horse will "throw black." But, generally speaking, one horse cannot be guaranteed to "throw black" with all mates. The mate of a true black horse may contribute the a dominant Agouti allele, which will suppress the black coloring and result in a bay foal. If a black is bred to a gray, the ensuing foal may also be gray. Other modifiers present in the mate may produce additional dilution colors or spotting patterns. Nonetheless certain individual pairings with appropriate DNA testing can, in some cases, be guaranteed to produce black.
References
- "Horse coat color tests" from the UC DavisVeterinary Genetics Lab
- "Introduction to Coat Color Genetics" from Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis. Web Site accessed January 12, 2008.
- (pdf) D.P Sponenberg and M.C. Weise, "Dominant black in horses" in Genetics Selection Evolution, Department of Biosciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, no 29, mars 1997, p. 403-408
- J Henner, PA Poncet, L Aebi, C Hagger, G Stranzinger et S Rieder, "Horse breeding: genetic tests for the coat colors chestnut, bay and black. Results from a preliminary study in the Swiss Freiberger horse breed", in Schweiz Arch Tierheilkd, Institut für Nutztierwissenschaften der ETH Zürich, n°29, 2002, p. 144(8):405-12