Study of Ancient Genes Reveals a Dark Skinned Europe Until 3,000 Years Ago
A new study of ancient DNA has completely changed our understanding of the peoples who lived in Stone Age and Bronze Age Europe. It was only about 1000 BC, well into the Iron Age, that we first saw light skinned individuals emerge on the continent.
The study, published in BiorXiv, concludes that lighter skin and associated features such as green or blue eyes probably evolved several times over the course of human history, in response to migration from African into areas with lower UV radiation such as Europe. The study reaches back as far as 45,000 years ago and concludes that, for the vast majority of that time, this evolutionary change had not occurred and Europeans shared the same skin tone as their African ancestors.
Absorption of UV radiation is essential for the production of Vitamin D and, all things being equal, paler skin is better at absorbing it. This would suggest that paler skins in more northern regions with less UV radiation would be a key advantage.
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The previous theoretical consensus was that lightening pigmentation would evolve gradually and in a linear fashion in response to the different conditions in Europe, but this was not the case. However there were other changes during the period which shed an interesting light on the evolution of Europeans.
While the skin remained dark, eye color changed in a less predictable fashion. Eyes got paler until the Mesolithic, the middle Stone Age between roughly 15,000 and 5,000 years ago. At this point Europeans were predominantly dark skinned and blue eyed (as were the Neanderthals of the region, an interesting bit of convergent evolution).
However from this point the number of dark eyes in the population began to increase again, for an unknown reason. Similarly, the team also saw evidence of localized variations suggesting that specific circumstances (and smaller, more isolated gene pools) could result in faster or more radical changes.
Take for example the Neolithic farmers of Western Eurasia. These populations were faced with a wildly different lifestyle to their ancestors, and the pace of change for these peoples was accordingly a swift one.
Gone were the semi-nocturnal hunter gatherer communities of forests and grasslands, adapted to long distance aerobic exercise and with their diet of meats and wild vegetables. In their place there was a people used to long daylight hours spent on heavy labor in a single place, tied to the land they cultivated.
These farmers, in isolated communities, slowly developed paler skin at varying rates, but all generally faster than the Stone Age predecessors. This suggests a change in behavioral habits was also key to developing lighter skin, and that the environment alone was not a genetic disadvantage of darker skinned Neolithic humans.
The changes to the diet of the Neolithic farmer resulted in less Vitamin D being taken in from foodstuffs. This meant that a paler skin was necessary for such communities to survive in health, and this is indeed what appears to have happened.
And of course the study is far from conclusive. There may well have been isolated populations in the early Stone Age with paler skin, but only more research can tell us for sure.
Header Image: Reconstruction of an early (between 37,000 and 42,000 years old) European Homo sapiens based on bones found in the cave Peştera cu Oase (Romania). Source: Daniela Hitzemann (photograph) / CC BY-SA 4.0.
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