Several ancestral populations have been recognized as the originators of current European genomes, but now new research out of Cambridge University, Trinity College Dublin, and University College Dublin have discovered an entirely new ancient lineage that contributed as well—one that derives from a people who settled in the Caucasus region some 45,000 years ago.
Before now, three groups were recognized as the progenitors of modern Europeans. After the expansion of humans out of Africa, one group colonized a large part of Europe, from Spain to Hungary. Another group settled in the eastern Mediterranean and Levant.
The third group, known as the Yamnaya, migrated into Europe around 5,000 years ago from central Eurasia—and it was the Yamnaya who bore both the previously recognized third strand and this new genetic heritage.
“The question of where the Yamnaya come from has been something of a mystery up to now,” explained co-author Dr. Andrea Manica, from Cambridge’s Department of Zoology, in a statement.
“We can now answer that as we’ve found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation. This Caucasus pocket is the fourth major strand of ancient European ancestry, one that we were unaware of until now,” he said.
The discovery was made after sequencing the genomes of human remains found in western Georgia—one over 13,000 years old, and another nearly 10,000 years old. Using this genome, the researchers determined that, following the expansion of humans from Africa, these hunter-gatherer ancestors settled where southern Russia meets Georgia, or the Caucasus region.
Caucasus mountains separated the population
But, unlike other populations, they did not expand into to the rest of Europe for thousands of years, but instead became trapped in the area during the “Glacial Maximum” era of the Ice Age. The Caucasus Mountains sheltered them from the worst weather of this period, but also sheltered them from other populations, leading to increasingly similar genes in the group as they interbred amongst themselves.
Finally, they were able to break free, bringing them into contact with other peoples, likely from further east. As this genetic mixing occurred, the Yamnaya culture developed: Horse-riding Steppe herders that swept through Europe around the start of the Bronze Age, thereby spreading their genes to the ancestors of nearly every modern European population.
“We knew that the Yamnaya had this big genetic component that we couldn’t place, and we can now see it was this ancient lineage hiding in the Caucasus during the last Ice Age,” said Manica.
Migration to Southeast Asia
Moreover, the Yamnaya appear to have migrated to Southeast Asia.
“India is a complete mix of Asian and European genetic components. The Caucasus hunter-gatherer ancestry is the best match we’ve found for the European genetic component found right across modern Indian populations,” said Eppie Jones, a PhD student from Trinity College who is the first author of the paper.
Which means a big genetic mystery across two continents seems to have just been solved.
“This is a major new piece in the human ancestry jigsaw, the influence of which is now present within almost all populations from the European continent and many beyond,” said Professor Daniel Bradley, leader of the Trinity team.
“The sequencing of genomes from this key region will have a major impact on the fields of palaeogeneomics and human evolution in Eurasia, as it bridges a major geographic gap in our knowledge,” added Professor Ron Pinhasi, a lead senior author from University College Dublin.
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Feature Image: Eppie Jones
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