Conserved distal promoter of the agouti signaling protein (ASIP) gene controls sexual dichromatism in chickens.

Brilliant plumage is typical of male birds, thus sexual plumage dichromatism is seen in many avian species; however, the molecular mechanism underlying this remains unclear. The agouti signaling protein (ASIP) is a paracrine factor that stimulates yellow/red pigment (pheomelanin) synthesis and inhibits black/brown pigment (eumelanin) synthesis in follicular melanocytes. In mammals, the distal promoter of the ASIP gene acts exclusively on the ventral side of the body to create a countershading pigmentation pattern by stimulating pheomelanin synthesis in the ventrum.