The Evolution of Dark Skin

A new study finds that humans first developed deep pigmentation to combat skin cancer

It is believed that thousands of years ago, before Homo sapiens travelled out of Africa, they all had dark skins. When humans migrated to parts of modern-day Europe, because of the weak sunshine in those regions, they developed fair skin to synthesise Vitamin D. However, because chimpanzees, from whom all humans have split, have pale skin under their hairy coats, it is believed that humans too were originally fair. An evolutionary process made them develop dark skins, and later when they migrated out of Africa, they again started developing fair skins.

A new study now claims that humans developed a dark skin tone to deal with skin cancer. According to the study, published in Proceedings of the Royal Society, the change occurred after ancient humans shed most of their body hair and ventured out into the sun-drenched African Savannah. The sun’s rays, it is claimed, exerted powerful selection pressure on ancient humans. Only those with darker and better protective skin could thus escape dying of skin cancer. They then passed their genes onto future generations.

The research was conducted on people with albinism in modern Africa. Albinism, an inherited disorder, prevents people from making melanin, a black or brown pigment. The research found that at least 80 per cent of all people with albinism from African countries like Tanzania and Nigeria die of skin cancer before their 30th birthday. The researchers point out that this link of albinism with skin cancer has also been noted in other tropical sunny regions besides Africa, like Panama.

The lead researcher, Mel Greaves, a cell biologist at the Institute of Cancer Research in the UK, told Live Science, “Cancer has been dismissed (for causing dark skin) by effectively all scientists in the past… They did so believing that skin cancer cannot be a selective force acting on survival and reproductive success, because in present-day white-skinned people, it is usually benign or impacts too late in life.”

cancerdark skinHomo sapiens