Amelanism in Mammals
The only pigments that mammals produce are melanins. For a mammal to be unable to chemically manufacture melanin renders it completely pigmentless. This condition is more commonly called albinism. Amelanistic mammals have white hair, pink skin, and eyes that have a pink, red, or violet appearance. Reddish eyes are due to the lack of pigment in the iris pigment epithelium. When the stroma is unpigmented but the iris pigment epithelium is not, mammalian eyes appear blue. Melanin in the pigment epithelium is critical for visual acuity and contrast.
Loss of melanogenesis function is linked to the gene that encodes tyrosinase. Certain alleles of this gene, TYR, at the Color locus, cause oculocutaneous albinism type 1 in humans and the familiar red-eyed albino conditions in mice and other mammals.
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