When evolution is not a slow dance but a fast race to survive

(Interesting article by Wendy Orent on fast evolution of Europeans. If Middle Easterns are actually Europe’ ancestors , then why they are still living in past and has not progressed? f,sheikh).

<em>Afghan refugee Maimuna, photographed in Kabul in 2016. <em>Photo by Hedayatullah Amid/Epa/REX</em></em>

We all know what Neanderthals looked like: the beetling brow ridges, thick nose, long skull, massive bone structure – and probably red hair and freckled skin. You might do a double-take if you saw one on the subway, wearing a suit, or you might not. But you would surely look twice at the hunter-gatherers that populated Europe between 7,000 and 8,000 years ago, whose DNA scientists are analysing now. They had dark skin and, very likely, bright-blue eyes, like the arrestingly beautiful child from Afghanistan you see in the photograph above. This combination essentially vanished from ancient Europe, replaced by light-skinned, brown-eyed farmers who moved in from the Middle East over the course of several centuries, and who looked like most of the population of southern Europe today.

These early farmers, who depended on milk, have the gene for lactose tolerance that is missing in the old hunter-gatherer population. They ate much less meat and far more starch than the original meat-eating Europeans, and depended both on milk and on sunlight for vitamin D – hence their lighter skin. As for the dark, blue-eyed people, they disappeared from Europe, swamped genetically by the invaders over time.

This is a tale of fast human evolution. New ways of living – farming crops, and herding animals rather than hunting – led to the rapid expansion of genes that took advantage of these cultural adaptations. The ancestral dark skin, probably inherited from our common forebears in Africa, could have been a disadvantage if most calories came from cultivated grains rather than meat from wild animals, rich in vitamin D. Blue eyes remained, though the form of the gene (called an allele) for blue eye colour is recessive, and easily swamped by alleles for brown eyes. So within some span of time – we can’t say exactly how long – ancient Europeans began to look quite different. There was also an influx of genes from east Asia, from peoples likely resembling the modern Chukchi and other native Siberian groups closely related to Native Americans. Ancient Europe was a melting pot, but certain alleles, for light skin and brown eyes, became dominant as the hunter-gatherer way of life receded against an influx of farmers and farming.

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