NEW YORK – Findings from an ancient DNA analysis suggest individuals from Siberia, Northeast Asia, and North Eurasia met and mixed in what is now the Lake Baikal region of Siberia, contributing to the ancestry of the earliest known populations in the Americas.
"This study reveals the deepest link between Upper Paleolithic Siberians and [the] First Americans," first author He Yu, an archaeogenetics researcher at the Max Planck Institute for the Science of Human History, said in a statement, noting that the results "could shed light on future studies about Native American population history."
For a study published in Cell on Wednesday, the researchers relied on targeted and metagenomic sequencing to profile SNPs and pathogen patterns in 19 ancient Siberian individuals dated as far back as the Upper Paleolithic period and into the Early Bronze Age.
"Modern humans have inhabited the Lake Baikal region since the Upper Paleolithic, though the precise history of its peoples over this long time span is still largely unknown," Yu and his co-authors explained.
Based on insights from more than 1.2 million variants present in the ancient individuals — including a 14,000-year-old "Upper Paleolithic" individual represented by a tooth fragment found at a site south of Lake Baikal called Ust-Kyakhta-3 — the authors saw genetic ties between the Upper Paleolithic Siberian population and Native American populations outside of the Arctic that appear to carry related ancestry.
The team also identified influxes of ancestry from northern Eurasia over the span of roughly 10,000 years, with admixed Siberian, North Eurasian, and Northeast Asian populations appearing in the region from the Neolithic period to the Bronze Age.
The complex genetic and cultural interactions that took place in and around Lake Baikal were underscored by the researchers' metagenomic sequence analyses, which uncovered sequences stemming from the plague-causing Yersinia pestis pathogen in two Bronze Age individuals with ancestry from western Eurasia.
The Y. pestis pathogens fell into an extinct "Late Neolithic to Early Bronze Age" (LNBA) lineage that has been previously linked to populations with Yamnaya steppe ancestry, they noted, though that ancestry was not found in the infected individuals themselves.
"Taken together, these results provide evidence for the presence of Y. pestis infections in the Lake Baikal region during the Early Bronze Age," the authors reported. "To our knowledge, this is the easternmost appearance of Y. pestis strains associated with the LNBA lineage, despite the lack of steppe-related ancestry in both infected individuals."
These and other population interactions gleaned from new and available population sequence data are consistent with "dynamic changes in the population structure of the Lake Baikal region," the authors concluded, noting that the study "reveals a widespread occurrence of the genetic ancestry that gave rise to the First People of the Americas in Upper Paleolithic Siberia."