DNA Links Europeans to Middle Eastern Farmers, Eurasian Nomads

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DNA Links Europeans to Middle Eastern Farmers, Eurasian Nomads

By Kurt Holden

"Analysis of DNA from modern humans supports other indications that a northward migration of farmers from ancient Turkey and the Middle East, beginning around 9,000 years ago, shaped Europe's genetic geography."--Bruce Bower, Science News, June 24, 1995.

Are you happiest puttering in your garden on a sunny summer weekend, or climbing into the car for a trip to the mountains, the beach, or just out on the open road? If your answer is both and you're of European origin, the explanation for your conflicting instincts may lie in your genes. Or so increasingly contentious scientists in human biology and scholars in Indo-European linguistics would have us believe, as they struggle to resolve conflicting data from both specialties.

In recent years some geneticists have contended that they can map a steady migration, generation by generation, of the neolithic farmers who invented agriculture in the Middle East's Fertile Crescent. The geneticists maintain that these Middle Easterners took their agricultural techniques north and west with them from modern-day Turkey into Eastern and Western Europe--displacing or absorbing the sparse populations of hunter-gatherers who had lived on the fringes of the retreating glaciers of the final ice age. The biological scientists base their thesis on blood samples gathered as part of a worldwide survey of human genetic variation.

That theory is not consistent with a central tenet of linguists who have postulated the spread of Indo-European languages throughout Europe (and Anatolia, Iran and the Indian subcontinent) by nomads from the Yamna culture of central Eurasia after their invention of wheeled vehicles some 5,500 years ago.

New evidence for the migration of Middle Eastern farmers is laid out in a study by Alberto Piazza, a geneticist at the University of Torino, and his colleagues published in the June 20 proceedings of the National Academy of Sciences. It is based upon blood samples gathered earlier under the direction of L. Luca Cavalli-Sforza, a geneticist at Stanford University, described in The History and Geography of Human Genes, published in 1994 by Princeton University Press.

Analyzing DNA from people in Europe and adjacent parts of Eurasia and the Middle East, Piazza's team looked for geographic patterns. Starting with genetic mutations common to people presently living in Turkey and the Middle East, they found fewer of these mutations in northern areas--indicating that the ancestors of northern Europeans had separated from the stock that remained in the Middle East before many of the mutations took place.

Piazza's team relates about one-fifth of the observed gene differences to a genetic split between populations in Europe's extreme north and those in southerly regions. These differences may have two causes, the team suggests. One may be differing adaptations to cold climates and the other to a separation of northern groups between those who spoke Uralic languages and those who spoke Indo-European languages.

The Middle East was an ancestral homeland for the people who now live in Europe.

A third map, based upon about one-tenth of the observed gene differences, shows how DNA characteristics that are concentrated in central Eurasia extend throughout Europe. The resulting patterns correspond roughly to archeological evidence for the movement of Yamna people from Eurasia into Europe. …