At a glance
Ancient-DNA analyses identify a Caucasus Lower Volga people as the ancient originators of Proto-Indo-European, the precursor to the massive Indo-European language family.
The population lived on the Eurasian steppe within the borders of current-day Russia during the Copper Age about 6,500 years ago, data show.
Findings indicate members of the group mixed with people to the west to form the distinct genome of the Yamnaya people, who went on to spread Indo-European languages across the world.
A pair of landmark studies has genetically identified the originators of the massive Indo-European family of 400-plus languages.
Results of the international ancient-DNA studies, published Feb. 5 in Nature and supported in part by the National Institutes of Health and National Science Foundation, place these linguistic pioneers within the borders of current-day Russia during the Eneolithic or Copper Age about 6,500 years ago. They were spread from the steppe grasslands along the lower Volga River to the northern foothills of the Caucasus Mountains.
The discovery marks a collaborative triumph that builds on decades of work by linguists, archaeologists, and geneticists.
It provides the missing piece from the century-old “steppe hypothesis,” which positions the birthplace of Indo-European languages — and their precursor, Proto-Indo-European, which predated writing — on the Eurasian steppe, where Russia and Ukraine stand today.
Earlier work had pointed to the ancient Yamnaya people of the steppe as the originators of Proto-Indo-European, but a sticking point was that ancient speakers of one extinct branch of Indo-European languages didn’t have Yamnaya ancestry. Some geneticists, including co-senior author David Reich of Harvard Medical School and Harvard University, hypothesized that an even older population was the ultimate source. The new studies identify that population as the Caucasus Lower Volga people.
“It’s the first time we have a genetic picture unifying all Indo-European languages,” said co-first author Iosif Lazaridis, research associate in human evolutionary biology in the Faculty of Arts and Sciences (FAS) at Harvard University.
Reconstructing the Yamnaya and predecessors
Scholars first noted similarities among the far-flung languages of Latin, Greek, and Sanskrit in the late 18th century. The steppe hypothesis, formulated during the 19th century and formalized in the 1950s, drew on linguistic reconstructions and archaeological evidence to home in on the geographic origins of Proto-Indo-European.
The DNA detectives in Reich’s lab have been pursuing Proto-Indo-European speakers for more than 15 years. In 2014, they shared key insights on “the profound mixing event” that shaped modern Europeans, with most descended from three highly differentiated populations.
The following year, the lab’s scientists offered a fuller picture of the continent’s Yamnaya set of ancestors. These storied nomadic pastoralists are known for likely being the first to herd on horseback and as early adopters, if not inventors, of oxen-towed wagons.
“They turned over the population of Europe with huge disruptions in Germany, Spain, Italy, and Hungary,” said Reich, professor of genetics in the Blavatnik Institute at HMS, professor of human evolutionary biology in FAS, and senior associate member of the Broad Institute of MIT and Harvard. “In Britain, there was a 90 percent-plus population replacement within decades.”
The 2015 paper credited the far-traveling Yamnaya with carrying Indo-European languages across Europe and into the Indian subcontinent. A subsequent series of papers, published by Reich’s lab and others, followed their genetic footprints into Greece, Armenia, India, and China.
“It’s like a tracer dye,” Reich said. “You can actually see Yamnaya ancestry everywhere these languages went.”
But researchers encountered a hitch in the Yamnaya line in the Anatolian peninsula, where an extinct set of Indo-European languages was spoken during the Bronze Age. Linguists have long believed they represent an early split from Proto-Indo-European. The 21st-century advent of ancient DNA science surfaced similar results.
“We know from cuneiform tablets that people such as the Hittites spoke Anatolian, but these people didn’t have Yamnaya ancestry,” Reich noted. “We looked hard, with lots of data. We didn’t find anything. So we hypothesized some deeper population was the ultimate source in Indo-European languages.”
The Caucasus Lower Volga people is that original source, the authors said.
The work uncovers new links between those people and both the Yamnaya and the ancient Indo-Anatolian speakers who inhabited an area that is now part of Turkey.
The Caucasus Lower Volga people mixed prodigiously with other groups in the region, the findings indicate.
“It’s a very early manifestation of some of the cultural traditions that later spread across the steppe,” said Reich.
Past and present converge
The Russia-Ukraine war forced an unusual splintering of the findings. The first paper, focused on the origins of Indo-European languages, draws on the ancient DNA of 354 individuals at archaeological sites in Russia and Southeastern Europe. The second, authored with researchers in Kyiv, is based on 81 ancient DNA samples drawn from Ukraine and Moldova. Also part of the analyses are previously reported genetic data on nearly 1,000 ancient individuals.
The first paper traces various lineages from the Caucasus Lower Volga people, including the Yamnaya and the Anatolians. The second paper provides rich new context on the Yamna, the Ukrainian term for Yamnaya. It finds evidence that the culture may have taken root somewhere near the present-day small town of Mykhailivka in the southern part of Ukraine.
“Where the worst of the fighting is happening right now — that’s the Yamnaya homeland,” said co-first author David Anthony, emeritus professor of anthropology at Hartwick College in New York, former visiting scholar in the Reich Lab, and author of a 2007 book on the Yamnaya’s role in disseminating Proto-Indo-European.
The findings reveal that a population of Caucasus Lower Volga people moved west and started mixing with locals, forming the distinct Yamnaya genome.
“We found that the Yamnaya descend from just a few thousand people living in a handful of neighboring villages from 5,700 to 5,300 years ago,” Reich said. “Their descendants developed a radically new economy that allowed them to follow their herds of livestock into previously inaccessible open steppe lands. This led to a demographic explosion, so that in a few hundred years Yamnaya descendants numbered many tens of thousands and were spread from Hungary to eastern China.”
Language isn’t the only tradition the Yamnaya carried on from their Caucasus Lower Volga forebears. Both cultures buried their dead in kurgans, or large tombs with earth mounded on top. Lazaridis noted that these graves attracted generations of archaeologists and have now enabled the genetic reconstruction of their makers’ origins.
“Suppose the Yamnaya had a different culture,” offered co-first author Nick Patterson, deputy head of the Reich Lab, an associate in FAS, and senior computational biologist at the Broad Institute. “Suppose they had cremated their dead. Chances are, we wouldn’t even know about this crucial culture in human history.”
Adapted from an article in the Harvard Gazette.
Authorship, funding, disclosures
“The genetic origin of the Indo-Europeans”
Reich is co-senior author with Ron Pinhasi of the University of Vienna. Leonid Vyazov is co-first author with Lazaridis, Patterson, and Anthony. Additional authors can be found in the paper.
The study was funded in part by Polish scientific project grant NCN OPUS 2015/17/B/HS3/01327, the Russian Science Foundation (grants 21-18-00026 and 22-18-00470), the Museum of the Institute of Plant and Animal Ecology (UB RAS) grant FWRZ-2021-0006, the National Institutes of Health (R01HG012287), the John Templeton Foundation (grant 61220), J.-F. Clin, the Allen Discovery Center (a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation), and the Howard Hughes Medical Institute. This study depended on support from the research computing group at HMS. Additional supporters can be found in the paper.
“A genomic history of the North Pontic Region from the Neolithic to the Bronze Age”
Lazaridis is co-first author with Alexey G. Nikitin of Grand Valley State University in Allendale, Michigan. Additional authors can be found in the paper.
The research was supported in part by the National Science Foundation (grants BCS-0922374 and BCS-2208558), the National Institutes of Health (grant HG012287), the John Templeton Foundation (grant 61220), J.-F. Clin, the Allen Discovery Center (a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation), and the Howard Hughes Medical Institute. Additional funders can be found in the paper.
