NEW YORK (GenomeWeb) – An ancient DNA study published online today in Nature suggests that large-scale human migration by steppe herders from Eastern Europe may have introduced Indo-European languages to other parts of Europe through interactions with other groups across the continent.
Investigators from the US, Australia, and elsewhere used an enrichment approach known as in-solution hybridization — coupled with deep sequencing of nearly 395,000 targeted SNPs — to assess multiple libraries made using samples from 69 individuals who lived in Europe an estimated 3,000 to 8,000 years ago.
Together with available data for more than two-dozen previously sequenced 25 ancient individuals, polymorphisms patterns present in the newly sequenced samples offered a peek at past population movement and mixing in Europe. The samples spanned groups as diverse as hunter-gatherers present as far back as about 43,000-years-ago to farmers in the Early Neolithic and Middle Neolithic period, and individuals from the Late Neolithic, Late Copper, Bronze, and Iron Ages.
For instance, the team determined that early farmers — belonging to groups that were related to one another — made their way from the Mediterranean to Spain and on to Germany and Hungary roughly 7,000 to 8,000 years ago, taking on more local hunter-gatherer ancestry over the few thousand years that followed.
In Russia, meanwhile, they saw signs that hunter-gatherers shared ancestry with the 24,000 year old Mal'ta individual from Siberia sequenced in 2013.
"Against this background of differentiated European hunter-gatherers and homogeneous early farmers, multiple population turnovers transpired in all parts of Europe included in our study," senior author David Reich, a genetics researcher affiliated with Harvard Medical School and the Broad Institute, and colleagues wrote.
In particular, their results suggest that the Eastern hunter-gather group appears to have mixed with populations from the Near East/Caucusus to form the so-called Yamnaya steppe herder population.
The steppe herder group, in turn, seems to have come into contact with populations in Western Europe around 4,500 years ago: ancient individuals from the Corded Ware culture in Central Europe had close genetic ties to the Yamnaya, though the steppe ancestry was absent in samples from Early or Middle Neolithic farmers.
The influence of that migration and ancestry seems to have been pronounced, long lasting, and entwined with the spread of Indo-European language, the team noted.
The Yamnaya steppe ancestry "persisted in all sampled central Europeans until at least [around] 3,000 years ago, and is ubiquitous in present-day Europeans," the study's authors wrote. "These results provide support for a steppe origin of at least some of the Indo-European languages of Europe."
"[T]he location of the proto-Indo-European homeland that … gave rise to the Indo-European languages of Asia, as well as the Indo-European languages of southeastern Europe, cannot be determined from the data reported here," they cautioned. "Studying the mixture of the Yamnaya themselves, and understanding the genetic relationships among a broader set of ancient and present-day Indo-European speakers, may lead to new insight about the shared homeland."