Paleface: If it is assumed that humans started out medium or dark-skinned, how long did it take for Europeans to lose much of that original pigment? An article in Science April 20 says maybe just 6,000 to 12,000 years. “This contradicts a long-standing hypothesis that modern humans in Europe grew paler about 40,000 years ago, as soon as they migrated into northern latitudes,” the article states, reporting on a March meeting of the American Association of Physical Anthropologists. Pale skin is said to have an adaptive value at high latitudes: “Under darker skies, pale skin absorbs more sunlight than dark skin, allowing ultraviolet rays to produce more vitamin D for bone growth and calcium absorption.” The new date was based on genetic studies that suggested a “selective sweep occurred 5300 to 6000 years ago” or up to 12,000 years ago, “given the imprecision of method”.

- posted by Alan Grey @ Thursday, April 26, 2007