Most scientists agree the development of black skin occurred in early humans primarily because of the ability of eumelanin to effectively absorb ultraviolet radiation, but they have debated exactly how this could have protected early humans against lethal diseases.
As well as affecting skin cancer risk, increased black melanin production could have given other benefits that helped individuals to pass on their genes to the next generation, such as preventing damage to sweat glands or the destruction of folate, which is important in foetal development.
While there could have been many benefits of having black skin in Africa (and retaining it in New Guinea), Professor Greaves argues that individuals with albinism and no protective benefit from melanin almost all die young from cancer.
Professor Greaves is Director of the new Centre for Evolution and Cancer at The Institute of Cancer Research (ICR). The Centre aims to gain new insights into how individual cancers evolve the process behind the development of drug resistance, and the often extraordinary genetic diversity within single tumours and to uncover clues in our evolutionary history that could help us understand why human cancers develop.
Professor Mel Greaves, Director of the Centre for Evolution and Cancer at The Institute of Cancer Research, London, said:
"Charles Darwin thought variation in skin colour was of no adaptive value and other investigators have dismissed cancer as a selective force in evolution. But the clinical data on people with albinism, particularly in Africa, provide a strong argument that lethal cancers may well have played a major role in early human evolution as an important factor in the development of skin rich in dark pigmentation - in eumelanin."
|Contact: Henry French|
Institute of Cancer Research