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. This movement is cited by linguists as evidence for a Central Asian origin for the Indo-European languages.

However, biostatistician Robert B. Sokal of the State University of New York at Stony Brook denies that the genetic data clarify the origins of Indo-European languages. He says that existing research is consistent with earlier genetic studies that found traces of an expansion of early farmers from Turkey into Europe. (See the Sept./Oct. 1993 Washington Report, p. 81.)

However, when a team under Sokal's direction looked for corresponding geographic patterns in related words in Indo-European languages, it found no linguistic evidence of an Eastern Turkey origin for Indo-European languages. "At this point, I can't substantiate any hypothesis of Indo- European origins," Sokal told the weekly Science News.

What seems increasingly certain is that the Middle East, where so many domesticated animals and plants originated, was an ancestral homeland for the people who now live in Europe—and their descendants all over the world. What remains to be learned is whether the Indo-European roots of every contemporary European language except Basque spread north and west with those early Middle Eastern farmers, were a later import of Eurasian nomads moving from east to west, or somehow evolved from the interaction of both.

Scientist Says Egyptian Fossils Are Oldest Primate Ancestor

Thirty-six-million-year-old skull, jaw and tooth fossils found over the past five years in Egypt are the earliest known common ancestor of apes, monkeys and human beings, according to Duke University anthropologist Elwin Simons.

"Egypt was once an important center of primate evolution," according to Simons, who described in the June 30 Science the findings of excavations he directed at a site about 60 miles southeast of Cairo in the Fayum desert. "This is the earliest animal known from the higher primates, the group that humans, apes and monkeys are in."

Older fossils that may be in the primate line of evolution have been found in China and Algeria, but they are too fragmentary for accurate classification. The most recent finds of the Egyptian species, called Catopithecus, permit it to be placed clearly "at the bottom of the human family tree, near the roots," according to Dr. Simons.

Although the Fayum fossils were found in what now is desert, Catopithecus lived in an area covered with tall trees bordering on the banks of a large lake not far from the Mediterranean Sea, according to the Duke University anthropologist. Other fossils from the same period found at the site include crocodiles, fish, water birds and rodents.

An animal smaller than a house cat, Catopithecus lived in the treetops, dining on fruit and occasional insects, Dr. Simons said. It probably had a long tail and "a monkey-like face, like a marmoset." He explained that if his interpretation is correct, all higher primates, from gorillas and chimpanzees to humans, evolved from this squirrel-sized animal.

Kurt Holden, a retired educational filmmaker, divides his time between the U.S. and the Middle East.