Blonde hair has evolved twice

About 5–10% of people from Melanesia, a group of islands northeast of Australia, have naturally blonde hair — the highest prevalence outside Europe. Yet people from the region have the darkest skin pigmentation outside Africa.

Hypotheses about the origins of this golden hair have included bleaching by sun and saltwater, a diet rich in fish, and the genetic legacy of Europeans or Americans. But a new study fingers a random genetic mutation instead, suggesting that blond hair evolved independently at least twice in human history.

Scientists discovered this after analysing saliva samples from 43 blonde and 42 dark-haired Solomon Islanders. A genome-wide scan pointed to a single strong difference between the groups at a gene called TYRP1. Further analysis revealed that a single-letter change in the gene accounted for 46 per cent of the population’s hair colour variation, with the blonde version of the gene being recessive to the dark hair version.

TYRP1 is known to be involved in skin and hair pigmentation in several species. In normally black mice, for example, a mutation in the gene produces light brown coats. A rare kind of human albinism is also caused by mutations in TYRP1, which produces reddish skin colour and ginger hair. Learn more here, here or here.

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2 Responses to “Blonde hair has evolved twice”

  1. Suzanne Elvidge Says:

    We posted about this on Genome Engineering at http://www.genome-engineering.com/blond-gene-in-melanesia-fair-hair-is-not-just-from-europe.html – it’s a really interesting bit of genetic research.

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