Along with black, chestnut is a base coat color that all other genes modify, called the extension gene. Both black and chestnut share the same gene, ee/EE, and in order for a horse to be chestnut, it must have extension ee.
The extension gene's recessive allele (e) produces pheomelanin, a red pigment, which creates the chestnut color.
Chestnut is one of the most common horse colors and is seen in nearly every breed of horse. It is categorized by red to brown colored coats lacking in true black pigment. A chestnut horse's mane and tail will be the same shade or a shade lighter than it's body. While chestnut is one of the most common coat colors, it's sheer diversity in pigmentation can cause confusion to even professional horse handlers; some chestnuts being light enough to look palomino, or dark enough to look black.
The extension gene's recessive allele (e) produces pheomelanin, a red pigment, which creates the chestnut color.
Chestnut is one of the most common horse colors and is seen in nearly every breed of horse. It is categorized by red to brown colored coats lacking in true black pigment. A chestnut horse's mane and tail will be the same shade or a shade lighter than it's body. While chestnut is one of the most common coat colors, it's sheer diversity in pigmentation can cause confusion to even professional horse handlers; some chestnuts being light enough to look palomino, or dark enough to look black.
Unlike most genes, the flaxen (F) gene must be dominant (FF/Ff) to not show up. Flaxen can be present in black base horses, but will not be visible, just like silver on red base horses. A horse with flaxen will have white, silvery, or cream colored mane and tail.
It is believed that the pangare(mealy) coloring is an extreme form of flaxen. Though pangare is not completely known, it has been disproven to be a separate gene. The inheritance of pangare is not understood, as foals with non-pangare parents have been born pangare and vice versa.
It is believed that the pangare(mealy) coloring is an extreme form of flaxen. Though pangare is not completely known, it has been disproven to be a separate gene. The inheritance of pangare is not understood, as foals with non-pangare parents have been born pangare and vice versa.
Genes that are in bold are active on the coat. Genes that are underlined are genes that the horse may carry, but will have no visible effect on the coat.
Gene Sequence
ee · aa · gg · crcr · dd · chch · F_ · zz · stysty · rbrb · rn+rn+ · sb1+sb1+ · w+w+ · to+to+ · oo · splspl · lplp · patn1patn1 · patn2patn2
Gene Sequence
ee · aa · gg · crcr · dd · chch · F_ · zz · stysty · rbrb · rn+rn+ · sb1+sb1+ · w+w+ · to+to+ · oo · splspl · lplp · patn1patn1 · patn2patn2