NEW YORK – Results from a new genomic study suggest a high-altitude site in the Indian Himalayan mountains called Roopkund Lake, or Skeleton Lake — known to fall on a contemporary religious pilgrimage route known as Nanda Devi Raj Jat — has been visited by diverse populations over the past 1,000 years, including migrants from the Mediterranean or South Asia who died there within the last few centuries.
"Roopkund Lake has long been subject to speculation about who these individuals were, what brought them to Roopkund Lake, and how they died," co-senior and co-corresponding author Niraj Rai, a researcher at the CSIR Centre for Cellular and Molecular Biology and the Birbal Sahni Institute of Palaeosciences, said in a statement.
Although unexpected, he and his colleagues explained, the heterogeneous genetic profiles, times of death, and dietary habits of the ancient Roopkund Lake individuals "have produced meaningful insights about an enigmatic ancient site."
Following from a past study that identified diverse mitochondrial haplogroups in dozens of ancient samples at Roopkund Lake, Rai and colleagues from India, the UK, US, and Germany did whole-genome sequencing on DNA from 38 skeletons and PCR-based analyses on 71 individuals. The data, published online today in Nature Communications, pointed to ancestry from three distinct genetic groups: one resembling present-day Indian populations, another from Southeast Asia, and third that was traced back to a Mediterranean population currently centered around Greece and Crete.
"The presence of individuals with ancestries typically associated with the eastern Mediterranean suggests that Roopkund Lake was not just a site of local interest, but instead drew visitors from across the globe," first author Éadaoin Harney, an organismic, evolutionary biology, and genetics researcher affiliated with Harvard University and the Max Planck-Harvard Research Center for the Archaeoscience of the Ancient Mediterranean (MHAAM), said in a statement.
Likewise, the concentration of ancient skeletons at the site previously prompted speculation that a single incident might have wiped out many people at once — a hypothesis that did not line up with the team's analyses.
"To shed light on the origin of the skeletons of Roopkund, we analyzed their remains using a series of bioarcheological analyses, including ancient DNA, stable isotope dietary reconstruction, radiocarbon dating, and osteological analysis," the authors wrote.
The researchers reported that 23 individuals, who had remains radiocarbon dated to more than 1,200 years ago, had South Asian ancestry similar to that documented in present-day populations in India. The other remains appeared to come from individuals who died much more recently, roughly 219 years ago, including one ancient individual who had ancestry from Southeast Asia and 14 individuals with eastern Mediterranean ancestry.
In a statement, co-senior and co-corresponding author David Reich, a researcher affiliated with MHAAM, Harvard Medical School, and the Broad Institute, further noted that the new analysis "raises the striking question of how migrants from the eastern Mediterranean, who have an ancestry profile that is extremely atypical of the region today, died in this place only a few hundred years ago."