Hair | Dark

Evolutionary biologists suggest that dark hair and skin evolved as an adaptation to intense solar radiation, particularly in equatorial regions. Biochemistry, Melanin - StatPearls - NCBI Bookshelf - NIH

: Pigment synthesis begins with the amino acid L-tyrosine , which is converted by the enzyme tyrosinase into dopaquinone. In the absence of high sulfur levels (cysteine), this precursor polymerizes into the dark eumelanin. Evolutionary Context dark hair

: Dark hair results from high levels of eumelanin produced by melanocytes in the hair follicle bulb. Evolutionary biologists suggest that dark hair and skin

: Most individuals with dark hair possess two functional copies of the MC1Rcap M cap C 1 cap R particularly in equatorial regions. Biochemistry

gene, which signals melanocytes to produce eumelanin instead of pheomelanin.