The Genetic Stratigraphy of Roopkund Lake: What DNA from the 'Skeleton Lake' Reveals About Mediterranean Migrants in the Himalayas

High in the Garhwal Himalayas, at an altitude of approximately 5,029 meters, lies Roopkund Lake. For decades, this small, snow-shrouded body of water has been known colloquially as "Skeleton Lake" due to the scattered remains of hundreds of humans visible beneath its frozen surface during the summer melt.

Local legend, preserved in traditional folk songs, attributes the mass of bones to a single catastrophic event. The story tells of a pilgrimage by Jasdhawal, a king of Kanauj, his pregnant wife, and their entourage. According to the legend, the group angered the mountain goddess Nanda Devi, who summoned a fierce storm of giant hailstones that killed the entire party instantly.

For years, early archaeological and anthropological surveys yielded conflicting estimates of when and why these individuals died. Some researchers suggested a single 9th-century military disaster, while others proposed an epidemic or a commercial caravan lost in a blizzard. However, a comprehensive paleogenomic study published in Nature Communications dismantled the single-event narrative, revealing that the skeletons belong to genetically distinct populations who died in at least two major episodes separated by approximately one thousand years.

Chronological and Genetic Stratigraphy

In genetics, stratigraphy refers to the analysis of different ancestral layers within a biological sample set over time. To reconstruct the history of Roopkund, an international team of scientists analyzed the mitochondrial, Y-chromosomal, and whole-genome DNA of 38 individuals, combining genetic data with accelerator mass spectrometry (AMS) radiocarbon dating.

The laboratory analysis revealed that the Roopkund skeletons do not represent a single biological population. Instead, the researchers identified three genetically distinct groups:

• Group A: This cohort represents the largest group, consisting of 23 individuals. Their genetic ancestry matches modern South Asian populations, though they do not cluster within a single specific caste or ethnic group. Radiocarbon dating places their deaths between the 7th and 10th centuries CE, consistent with a medieval timeline.
• Group B: This group consists of 14 individuals whose genetic profiles do not align with South Asian ancestry. Instead, their genomes show a strong affinity to modern populations of the eastern Mediterranean, specifically present-day Greece and Crete.
• Group C: A single individual was identified with ancestry closest to modern East Asian populations, specifically clustering with groups from Southeast Asia.

The temporal gap between these groups is stark. While the South Asian individuals (Group A) died approximately 1,200 years ago, the Mediterranean-allied individuals (Group B) and the East Asian individual (Group C) died much later, around 1800 CE.

Dismantling the Single-Event Myth

The radiocarbon dating of the Group B skeletons—ranging from the late 18th to the early 19th century—rules out the possibility that they were part of the medieval pilgrimage associated with the Kanauj legend. The presence of individuals with eastern Mediterranean ancestry in a remote Himalayan pass during this period presents a historical puzzle.

The genetic data shows no evidence of close familial relationships among the Group B individuals, suggesting they were a cohort of unrelated men and women. Chemical analyses of stable isotopes from the bones also support this distinction. Isotope ratios of oxygen and carbon reflect an individual's childhood diet and geographic environment. The isotopic signatures of the Group B skeletons indicate they grew up in a Mediterranean climate rather than the Indian subcontinent, confirming they were first-generation travelers who died shortly after arriving in the Himalayas.

⚖ Scholarly Debate: The Purpose of the Journeys

The genetic and chronological findings have led to new academic inquiries regarding why these diverse groups were traveling through the high-altitude pass of Roopkund.

• The Medieval South Asians (Group A): There is general agreement among historians and archaeologists that the 9th-century Group A individuals were likely pilgrims. Roopkund lies along the route of the Nanda Devi Raj Jat, a major pilgrimage path that continues to be traversed today. The discovery of parasol shafts and other ritual objects near the lake supports the hypothesis that these individuals were participating in a religious procession when they met their deaths, possibly due to sudden exposure or a severe storm.
• The Mediterranean Travelers (Group B): The presence of Mediterranean migrants in the early 19th century is subject to ongoing scholarly debate. One hypothesis suggests they were merchants, diplomats, or travelers exploring the Himalayan frontier during the period of expanding British colonial administration in India. However, the lack of recorded historical documentation of a Mediterranean expedition perishing in the region has led some researchers to suggest they may have been part of a military contingent or an unrecognized geographic survey party. No weapons or military gear have been recovered to definitively prove a military origin.

Implications for Paleogenomics

The findings at Roopkund Lake demonstrate the utility of ancient DNA in correcting historical narratives. Relying solely on physical anthropology or local folklore would have left the complex, multi-era nature of the site hidden. By analyzing the genetic material directly, researchers proved that the "Skeleton Lake" was not the site of a single tragedy, but a recurrent graveyard for travelers separated by geography, ancestry, and centuries of time.

Sources:

• Harney, É., Nayak, A., Patterson, N. et al. Ancient DNA from the skeletons of Roopkund Lake reveals Mediterranean migrants in India. Nature Communications (2019).