Genetic Roots of Europeans Revealed
Friday, April 26th, 2013April 26, 2013
The genetic roots of modern Europeans do not stretch as deep into prehistory as most scientists had thought, reports a joint team of German and Australian scientists. A new analysis of ancient skeletons found in Germany indicates that a major population upheaval occurred in Europe around 4,000 B.C., when long-established populations were suddenly displaced by other farming people moving into the region. These more recent migrants, rather than the older populations, seem to be the direct ancestors of most living Europeans today.
Archaeologists have found fossils and stone tools that show early humans first lived in Europe more than 700,000 years ago. The Cro-Magnon people hunted throughout Europe from about 35,000 years ago to 10,000 years ago. By about 6000 B.C., farming peoples migrated into Europe from the Near East. Most scientists had believed that modern Europeans were descended from these ancient populations. The new findings, however, suggest that most living Europeans are descended from farmers who migrated into the region only about 4,500 years ago.
A megalithic monument near Carnac, France, is one of many of these stone structures made by prehistoric people. The best-known monuments are in western Europe and the Mediterranean region. These sites were built between about 4500 and 1400 B.C., during the Neolithic period and early Bronze Age. The builders made them for religious purposes or as burial places. (© Joe Cornish, Tony Stone Images)
The scientists based their conclusions on an analysis of DNA from 39 ancient skeletons excavated from the Mitelelbe Saale region, near Lepzig. The analysis was published April 23 in the online journal Nature Communications. The team focused their study on mitochondrial DNA (mtDNA)–a form of DNA found outside the chromosomes in cellular structures called mitochondria–that was preserved in the bones. In humans, mtDNA is inherited only from the mother. This makes the material useful to biologists for helping to determine relationships between groups. The scientists chose to examine a particular variety of mtDNA known as haplogroup H, the most common mtDNA variety in Europe, found in about 40 percent of Europeans today. However, haplogroup H is not common in the mtDNA from skeletons of Cro-Magnons or other early European hunter-gatherers, suggesting they made little genetic contribution to modern European populations.
The mtDNA from skeletons dated to the early Neolithic period of Europe, about 7,500 years ago, shows that farmers from the Near East migrated into Europe carrying a version of the haplogroup H with them. However, the international team found that by the Middle Neolithic, around 4,500 years ago, this early version of haplotype H was suddenly replaced by the version seen in modern Europeans.
Scientists are not certain where this newer haplotype H originated. But such a rapid replacement could only result from the migration of new populations into the region. The research shows that the movement of populations in prehistory and the genetic history of modern populations is much more complex than scientists had thought.
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