Europeans are descended from at least three different ethnic groups, or tribes, according to a new study.
Investigators knew modern humans in Europe shared genes with Middle Eastern farmers, as well as with European hunters. This new study reveals a connection between ancient European populations and people of northern Eurasia, who crossed the Bering Strait, becoming the first Americans. This suggests a connection between the people of Europe and Native Americans.
Middle Eastern farmers, as well as ancient Europeans, can trace their ancestry back to a people called "basal Eurasians," unknown until recently. Researchers believe populations of southern Europe have more Middle Eastern blood than their northern counterparts, possibly accounting for their darker features.
"Prior to this paper, the models we had for European ancestry were two-way mixtures. We show that there are three groups. This also explains the recently discovered genetic connection between Europeans and Native Americans. The same Ancient North Eurasian group contributed to both of them," David Reich, professor of genetics at Harvard Medical School, said.
Researchers examined DNA from 2,300 modern people from around the globe, as well as nine ancient humans, who once lived in Germany, Luxembourg and Sweden. Of these ancient remains, eight were hunter-gatherers who lived 8,000 years ago, while the ninth subject was a farmer who lived 1,000 years later. Genetic sequences taken from other ancient farmers were also included in the genetic investigation. A dramatic change between genetic codes of hunter-gathers and farmers suggested a large-scale movement of people from the Middle East into Europe soon after the development of agriculture on the continent.
"Nearly all Europeans have ancestry from all three ancestral groups. Differences between them are due to the relative proportions of ancestry. Northern Europeans have more hunter-gatherer ancestry -- up to about 50 percent in Lithuanians -- and Southern Europeans have more farmer ancestry," Iosif Lazaridis, a researcher on Reich's team, stated in a press release.
"We model these populations' deep relationships and show that early European farmers had ~44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages," the study summary states.
The existence of Northern Eurasian populations was first deduced from genetic codes which remain in modern humans. It was not until January, though, that the first specimens of the ancient society were discovered in northern Russia.
The genetic code of DNA degrades over time, making analysis of ancient samples challenging. This limited the amount of information available to researchers in the study. Other groups, in addition to the three now recognized, may have contributed to the ancestry of Europeans, according to Reich.
Study of the lineage of European populations and the previously little-known "basal Eurasian" people was detailed in the journal Nature.
