Why are Europeans obsessed with skin color

How dark skin came about

Charles Darwin was already concerned with the problem: Why do different human populations have different skin colors? The great British naturalist suspected - similar to the US anthropologist Jared Diamond recently - that sexual selection plays a decisive role: when choosing a partner, we would simply prefer people of similar skin type.

The alternative thesis to sexual selection is that of natural selection: The respective skin color would offer a survival advantage in the respective inhabited region. This theory was formulated in 2000 by the US anthropologists Nina Jablonski and George Chaplin and substantiated with world maps on which the strength of the respective regional ultraviolet radiation was compared with the skin colors of the people living there and which showed a high degree of agreement.

The argument of the two researchers: A high proportion of eumelanin in the skin, which ensures dark skin pigmentation, protects against high UV radiation. If, on the other hand, the UV radiation is only low, a high proportion of pheomelanin - i.e. light skin - helps in the production of vitamin D.

However, two questions remain unanswered: When did the dark skin color develop? And what exactly was the selection advantage that drove this development? New genetic analyzes suggest that a high proportion of eumelanin developed in the skin between 1.2 and 1.8 million years ago.

Protection against DNA damage

Our ancestors - like the chimpanzees - were likely to have had fair skin beforehand. But after the gradual loss of body hair due to heat reasons, stronger protection against harmful UV radiation was necessary. And that was offered by eumelanin, which effectively prevents DNA damage.

This thesis has now been accepted by most scientists. It remains to be seen what the decisive selection advantage of dark skin was. Dark pigmentation not only protects against skin cancer, but also against damage to the sweat glands and the destruction of folic acid, which is essential for the development of the fetus.

The British researcher Mel Greaves now believes he has found the answer to this question. He assumes that deadly "black" skin cancer, ie malignant melanoma, was responsible for the selection. He justifies his hypothesis set up in the "Proceedings of the Royal Society B" with the extremely high rate of skin cancer in albinos living near the equator, which cannot produce eumelanin in the skin due to a genetic defect.

Greaves found that at least 80 percent of fair-skinned people living in countries like Tanzania or Nigeria develop fatal skin cancer before they turn 30. For the researcher it is therefore obvious that skin cancer ultimately caused the dark skin color. (Klaus Taschwer, DER STANDARD, February 26, 2014)