(CN) — A team of researchers has assessed the population history of the region of Lake Baikal in Siberia using human population genetics, ancient pathogen genomics and isotope analysis, and found a clear transcontinental connection between the native people of Siberia and North America.
The researchers' findings, published Wednesday in the journal Cell, describe human mobility and connectivity across Eurasia during the early Bronze Age — a period characterized by increasing social and technological advancements.
Lake Baikal has been home to many modern humans since the Upper Paleolithic era and they left behind a rich archaeological history. Analysis of the ancient genomes retrieved from this region has revealed multiple genetic turnovers and admixture events, suggesting that human mobility was responsible for the transition from the Neolithic to the Bronze Age and the complex cultural interactions that followed. However, it remains largely unknown as to when and how these interactions took place.
The study, led by the Department of Archaeogenetics at the Max Planck Institute for the Science of Human History, reports on scientist’s discovery of 19 newly sequenced ancient human genomes from the region of Lake Baikal, including one of the oldest known individuals reported from this region. The team sheds light on the population history by revealing the deep mysterious connections with the first peoples of the Americas, dating as far back as the Upper Paleolithic period.
"This study reveals the deepest link between Upper Paleolithic Siberians and First Americans," the study’s lead author He Yu said. "We believe this could shed light on future studies about Native American population history."
Previous studies have shown the existence of a connection between Siberian and American populations but this research conclusively confirmed such a connection in an analysis of a 14,000-year-old individual, the oldest to date to carry the mixed ancestry present in Native Americans. With the help of cutting-edge techniques in molecular biology, the researchers analyzed an ancient, extremely fragmented tooth excavated in 1962 at the Ust-Kyahta-3 dig site in Russia and generated what is known as a shotgun-sequenced genome.
They found that this individual from southern Siberia, along with a younger Mesolithic one from northeastern Siberia, shares the same genetic mixture of Ancient North Eurasian (ANE) and Northeast Asian (NEA) ancestry that is often found in Native Americans. This discovery suggests that the ancestry, which later came to be the Native Americans in North and South America, was much more widely distributed than previously believed.
The evidence also suggests that the population in question experienced frequent genetic contacts with NEA populations, which then resulted in mixed populations spanning the length of time.
"The Upper Paleolithic genome will provide a legacy to study human genetic history in the future," said Cosimo Posth, another author of the paper. He also noted that further genetic evidence from the Upper Paleolithic Siberian groups will be needed to determine when and where the ancestral gene pool of Native Americans came together.
The study also shows connectivity within Eurasia, both in human and pathogen genomes and as seen by stable isotope analysis. By combining all this evidence of a prehistoric web of connections, the researchers produced a detailed picture of the population history in the Lake Baikal region.
They also discovered evidence of contact between southern Siberian and western Eurasian steppe populations from the presence of Eastern European steppe-related ancestry in the time before the Bronze Age. This evidence surprisingly came in the form of Yersinia pestis, the plague-causing pathogen, which points to even further wide-ranging contacts.
Although it has been thought that the spreading of Y. pestis was caused by migrations from the steppe, the two individuals with the pathogen analyzed in this study were genetically like individuals from northeastern Asian. Isotopic analysis of one of the infected individuals revealed a non-local signal, suggesting that their origins were outside the region of discovery.
The particular strains carried by these two individuals most closely resembles a strain identified in an individual from the Baltic region of northeastern Europe. This evidence further supports the idea of high mobility of those Bronze Age pathogens and likely also people.
"This easternmost appearance of ancient Y. pestis strains is likely suggestive of long-range mobility during the Bronze Age," said Maria Spyrou, one of the study's co-authors, in a statement accompanying the study.
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