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Cancer proposed as spur for evolution of dark-skinned ancestors

Fatal reactions to sunlight may have triggered a protective shift away from pale skin

BEYOND THE PALE  In several population studies, African albinos, represented here by a heavily freckled young man, frequently died young from skin cancers. Such cancers drove the evolution of dark skin early in Homo evolution, a new paper proposes. 

Common forms of skin cancer were Stone Age killers that prompted the evolution of black skin among human ancestors in Africa, a controversial new analysis concludes.

Evidence gathered over the last 40 years shows that albinos living in tropical parts of Africa and Central America, where they are constantly exposed to high levels of ultraviolet radiation from the sun, frequently develop skin cancer and die young from it, says biologist Mel Greaves of the Institute of Cancer Research in London.

Early members of the Homo genus in Africa were probably pale skinned and spent much of their days hunting and foraging in direct sunlight, Greaves asserts. Researchers generally agree that the loss of most body hair helped hominids control body temperature in tropical savannas.

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