New Delhi: A study conducted by an international team of scientists has revealed that the mysterious skeletons of Roopkund Lake - once thought to have perished during a single catastrophic event -- belong to genetically highly distinct groups that died in multiple periods in at least two episodes separated by one thousand years.
The study, published this week in Nature Communications, involved an international team of 28 researchers from institutions in India, the United States and Europe.
Situated at over 5000 meters above sea-level in the Himalayas, the presence of the skeletal remains had long puzzled researchers, earning the water body the nickname Skeleton Lake.
The study reveals that the site has an even more complex history than imagined. The genome sequencing of 38 individuals revealed that there were at least three distinct groups among the Roopkund skeletons.
The first group comprises 23 individuals with ancestries that are related to people from present-day India, who do not appear to belong to a single population, but instead derived from many different groups.
Surprisingly, the second largest group is made up of 14 individuals with ancestry that is most closely related to people who live in the eastern Mediterranean, especially present-day Crete and Greece.
A third individual has ancestry that is more typical of that found in Southeast Asia. "We were extremely surprised by the genetics of the Roopkund skeletons.
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," said Eadaoin Harney of Harvard University in the US.
Radiocarbon dating indicates that the skeletons were not deposited at the same time, as previously assumed. Instead, the study found that the two major genetic groups were actually deposited approximately 1000 years apart.
First, during the 7th-10th centuries, individuals with Indian-related ancestry died at Roopkund, possibly during several distinct events, researchers said.
It was not until sometime during around 1800 AD that the other two groups, likely composed of travellers from the eastern Mediterranean and Southeast Asia arrived at Roopkund Lake, they said.