Ancient DNA Sheds Light on a Previously Unknown Himalayan Population From 1,500 Years Ago

Researchers have uncovered evidence of a previously unrecognized group that inhabited Ladakh, in northern India, approximately 1,500 years ago. Genetic material extracted from remains in the Old Lady Spider Cave uncovers a distinctive ancestry blend combining South Asian and Tibetan genetic traits. Due to the scarcity of ancient South Asian DNA, findings like these are crucial for piecing together the migratory and cultural exchanges across the Himalayan region.

The skeletal remains belong to 10 individuals uncovered in 2021 at a high-altitude cave situated roughly 4,000 meters (13,100 feet) above sea level. This cave is located in Ladakh, a key area historically known for its role as a crossroads between South Asia, Tibet, and Central Asia along ancient trade pathways.

Featured in the journal Science Advances, the research employed genetic sequencing to analyze the origins of these ancient individuals and compared their DNA to thousands of both ancient and current genomes. Their findings indicate the existence of a group never before documented through genomic evidence.

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Uncovering a Hidden Population in the Himalayas Through Ancient DNA

Initially, the team verified the remains' age using radiocarbon dating. DNA was then extracted from the bones and tissues, with the genetic sequences compared against a large repository of human genomes. This investigation revealed an unexpected genetic composition. The genomes from the Old Lady Spider Cave individuals displayed an almost equal split between two ancestral lineages.

Half of their genetic makeup was traced to populations akin to modern North Indians, while the other half was linked to ancient Tibetan groups. This rare mix underscores a unique historical identity for this population.

These results imply that communities in the Himalayan region were actively part of broader demographic movements rather than existing in isolation.

Tracing Ancient Human Migrations Through DNA

The researchers further examined the lengths of inherited DNA segments from each ancestral source. Such segments help reveal the timing of mixture events between populations.

As two populations interbreed, shared DNA becomes fragmented into smaller pieces with each generation. By studying these fragment sizes, scientists can estimate when the original interbreeding occurred. The evidence indicates that the South Asian and Tibetan-related groups started mixing approximately 2,800 years ago, nearly 1,300 years before the burial of the cave’s inhabitants.

The authors note that this mixing timeframe does not necessarily pinpoint Ladakh as the precise location; rather, the genetic findings mark the start of gene flow between these groups prior to the archaeological record in this region.

The Enduring Legacy of an Ancient Himalayan Population

Beyond uncovering skeletal remains, the team identified genetic links that demonstrate the survival of this ancient population’s heritage within present-day Himalayan communities.

The research connects the Old Ladakh group to contemporary ethnicities, such as the Minero and Balti peoples of Ladakh. These modern populations retain portions of the DNA from their ancient predecessors who lived in this area over a millennium ago.

“This implies genetic drift shared between these groups and the Old Ladakh individuals, as expected for flow of Old Ladakh–related people into the ancestors of these groups. Thus, the Old Ladakh population did not completely disappear and instead left a legacy in present-day people,” the authors stated.

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