Modern Europe’s genetic history starts in Stone Age
- Jun 27, 2014
- 5 min read
Europeans as a people are younger than we thought, a new study suggests. DNA recovered from ancient skeletons reveals that the genetic makeup of modern Europe was established around 4,500 B.C. in the mid-Neolithic—or 6,500 years ago—and not by the first farmers who arrived in the area around 7,500 years ago or by earlier hunter-gatherer groups.
“The genetics show that something around that point caused the genetic signatures of previous populations to disappear,” said Alan Cooper, director of the Australian Centre for Ancient DNA at the University of Adelaide, where the research was performed.
“However, we don’t know what happened or why, and [the mid-Neolithic] has not been previously identified as [a time] of major change,” he said.
Furthermore, the origins of the mid-Neolithic populations that did form the basis of modern Europe are also unknown.
“This population moves in around 4,000 to 5,000 [B.C.], but where it came from remains a mystery, as we can’t see anything like it in the areas surrounding Europe,” Cooper said.
The surprising findings are part of a new study, published in this week’s issue of the journal Nature Communications, that provides the first detailed genetic history of modern Europe.
The study shows that “relatively recent migrations seem to have had a significant genetic impact on the population of Central Europe,” said study co-author Spencer Wells, who leads National Geographic‘s Genographic Project.
In human mitochondrial genetics, Haplogroup H is a human mitochondrial DNA (mtDNA) haplogroup that likely originated in Southwest Asia[1] 20,000-25,000 YBP. Haplogroup H is the most common and most diverse maternal lineage in Europe, in most of the Near East and in the Caucasus region. The Saami of Lapland are the only ethnic group in Europe who have low percentages of haplogroup H, varying from 0% to 7%.
The spread
Ancient DNA is painting a remarkable picture of the period of European prehistory known as the late Neolithic/early Bronze Age. It’s showing that after the collapse of genetically Near Eastern-like farming populations of middle Neolithic Central Europe – probably as a result of climate fluctuations, disease, famine and increasing violence – the vacuum was filled by genetically much more European-like groups from the eastern and western peripheries of Neolithic Europe.
First came the settlers from the east, belonging to the vast archeological horizon known as the Corded Ware Culture (CWC). About three hundred years later they were joined in Central Europe by migrants from the Atlantic Fringe, belonging to the Bell Beaker Culture (BBC). During the early Bronze Age, the CWC disappeared, and was replaced by the Unetice Cultre (UC), which briefly overlapped with the late BBC.
Ancient DNA recovered to date suggests that the Bell Beakers were genetically the archetypal Western Europeans, characterized by Western European-specific mtDNA H subclades and Y-chromosome haplogroup R1b. Interestingly, R1b has also been found among remains of aboriginals from the Canary Islands, just off the coast of northwest Africa. It might be a stretch to attribute this directly to the Bell Beakers, but they were certainly capable sailors, so perhaps not?
On the other hand, the CWC and UC populations appear to have been Eastern Europeans to the core, with low levels of mtDNA H and showing mtDNA affinities to Bronze Age Kurgan groups of Kazakhstan and South Siberia. We also know that Y-chromosome haplogroup R1a was present among the CWC of Germany, and it reached frequencies of almost 100% among the Kurgan samples from South Siberia and the European-like mummies of the Tarim Basin in what is now Western China.
So it seems everything is falling into place, with ancient DNA, archeology, and modern European genetic substructures all showing basically the same phenomenon. However, for a while now the ever more precise phylogeography of R1b has been hinting that this haplogroup might have expanded across Europe from the east. That’s because the most basal clades of R1b are found in West Asia, and its SNP diversity decreases sharply from east to west across Europe.
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