The Agouti gene is responsible for determining whether a mammal's coat is banded (agouti) or of a solid color (non-agouti).[1] The chief product of the Agouti gene is Agouti signalling peptide (ASP), but there are a number of alternative splice products.
In dogs, the Agouti gene is associated with various coat colors and patterns, including sable and tan points.[2]
In horses, the Agouti gene suppresses the action of the extension locus that produces black pigment (eumelanin) into point coloration on the mane, tail, lower legs and tips of the ears, thus allowing the underlying red pigment, pheomelanin, to appear on the body. This produces the color known as bay.
Mice that are heterozygous for the Agouti yellow allele have yellow coats and tendencies towards obesity. Mice that are homozygous for the Agouti yellow allele have the lethal gene. Mice that are homozygous for the non-agouti allele and non-agouti-yellow allele have non-agouti coat color (such as black).