A single receptor protein switch determines whether mammals produce light or dark pigment

Evidence

Mc1r acts like a switch because it flips between two alternative contortional states, and this change in shape alters the production of pigment. When Mc1r is twisted into one of its shapes it is relatively inactive, and pigment cells produce a pale yellow pigment called “phaeomelanin.” When it switches to its alternate and more active shape, then the cells begin producing a different pigment called melanin. Melanin is a deep, dark brown, and fur infused with melanin results in brown mice. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 618

Categorization

• DEFINE: Explains Mc1r, phaeomelanin, and melanin as the molecular basis of fur color.
• XREF: connects to: Predation on a new background drove rapid genetic color evolution in mice

Related

• Predation on a new background drove rapid genetic color evolution in mice (similarity 0.80)
• Two mutated genes drove the mouse population’s shift to white fur (similarity 0.80)