If an antagonist, such as agouti-signaling protein or beta-defensin in dogs, comes into play, the production of dark eumelanin stops, and melanocytes produce orange pheomelanin instead.

Five different color patterns in dogs controlled by promoter variants at the gene for agouti signaling protein. The activity of the ventral promoter (VP) or the hair cycle specific promoter (HP ...

For instance, in normal, healthy mice, the agouti genes are kept in the "off" position by the epigenome, which attaches methyl groups to the corresponding regions of DNA, resulting in the DNA's ...