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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, and the underlying skin color of a horse does not change, absent disease. The basic outline of equine coat color genetics has largely been resolved, and DNA tests to determine the likelihood that a horse will have offspring of a given color have been developed for some colors. Discussion, research, and even controversy continues about some of the details, particularly those surrounding spotting patterns, color sub-shades such as "sooty" or "flaxen", and markings. ==Basic coat colors== Genetically, all horses start out as either chestnut, called "red" by geneticists, represented by the absence of the extension gene ("e"); or black based on the presence of the extension gene ("E"). Therefore, red ("ee") and black ("EE" or "Ee") are the two base colors.〔http://www.thehorse.com/articles/31651/equine-coat-color-genetics-101〕 The Bay color is expressed when a common genetic modifier, 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 commonly seen horse color phenotypes are identified by the following terms: * Bay: Body color ranges from a light reddish-brown to very dark brown with "black points". (Points refer to the mane, tail, and lower legs.) The main color variations are: * * Dark bay: very dark red or brown hair, difficult to distinguish from seal brown. Sometimes also called "black bay", "mahogany bay", or "brown". * * Blood bay: bright red hair; often considered simply "bay". * * 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 (At), but it is not the cause of all forms of dark bay. Informally, "brown" is applied to many distinct coat colors. Most often, horses described by casual observers as "brown" are actually bay or chestnut. In the absence of DNA testing, chestnut and bay can be distinguished from each other by looking at the mane, tail and legs for the presence of black points. * Chestnut: A reddish body color with no black. Mane and tail are the same shade or lighter than the body coat. The main color variations are: * * Liver chestnut: very dark brown coat. Sometimes a liver chestnut is also simply called "brown". * * Sorrel: Reddish-tan to red coat, about the color of a new penny. The most common shade of chestnut. * * Blond or light chestnut: seldom-used term for lighter tan coat with pale mane and tail that is not quite a dun. * Gray: A horse with black skin but white or mixed dark and white hairs. Gray horses can be born any color, and lighten as they age. Most will eventually gray out to either a complete white or a "fleabitten" hair coat. Most "white" horses are actually grays with a fully white hair coat. A gray horse is distinguished from a white horse by dark skin, particularly noticeable around the eyes, muzzle, flanks, and other areas of thin or no hair. Variations of gray 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 fully white-haired horse that develops red hairs flecked throughout the coat. * * Rose gray: a gray horse with a reddish or pinkish tinge to its coat. This color occurs with a horse born bay or chestnut while the young horse is "graying out". 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Equine coat color」の詳細全文を読む スポンサード リンク
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