Evolution of Skin Color


click for full-zise image
Pigmentation is a complex process involving several pathways and many genes. Pigmentation protects skin from damage by UV radiation, which is clearly a desirable trait in regions with high exposure to the sun. As humans migrated further away from sunny latitudes, heavy pigmentation became a handicap because humans need to absorb some UV to generate vitamin D. It is hypothesized that mutations reducing pigmentation became prevalent in northern European populations to allow the absorption of more UV. Recently researchers have discovered several mutations in other organisms that are also found in human populations.

A mutation in zebra fish, named golden, results in pale fish compared to "wild type" (the more commonly occurring form). By searching sequencing databases, the gene responsible was found to be very similar to a gene found in humans. Research in sticklebacks has allowed researchers to identify another gene, kitlg, which also plays a role in pigmentation in both the fish and humans. Another interesting study showed that some Neandertals shared a mutation in the pigmentation gene MC1R, which results in red hair and pale skin.


Fish Sheds Light on Human Skin Color
EurekAlert from AAAS

A fish of a different color
Understanding Evolution

Professor Keith Cheng's Website (see the bottom of the page for an interview with Dr. Cheng about his pigmentation research)

Skin Color Evolution in Fish and Humans Determined by Same Genetic Machinery
Science Daily, Dec. 13, 2007