Genetic history of Himalayan populations found

A recent research has found out the genetic make-up of high-altitude Himalayan populations which has remained remarkably stable despite cultural transitions and exposure to outside populations through trade.

In a collaborative study by the University of Oklahoma, University of Chicago, University of California, Merced, and Uppsala University, researchers conducted the first ancient DNA investigation of the Himalayan arc, generating genomic data for eight individuals ranging in time from the earliest known human settlements to the establishment of the Tibetan Empire.

"In this study, we demonstrate that the Himalayan mountain region was colonized by East Asians of high altitude origin, followed by millennia of genetic stability despite marked changes in material culture and mortuary behavior," said researcher Christina Warinner.

Since prehistory, the Himalayan mountain range has presented a formidable barrier to population migration, while at the same time its transverse valleys have long served as conduits for trade and exchange.

Yet, despite the economic and cultural importance of Himalayan trade routes, little was known about the region's peopling and early population history. The high altitude transverse valleys of the Himalayan arc were among the last habitable places permanently colonized by prehistoric humans due to the challenges of resource scarcity, cold stress and hypoxia.

The modern populations of these valleys, who share cultural and linguistic affinities with peoples found today on the Tibetan plateau, were commonly assumed to be the descendants of the earliest inhabitants of the Himalayan arc.

However, this assumption had been challenged by archaeological and osteological evidence suggesting these valleys may have been originally populated from areas other than the Tibetan plateau, including those at low elevation.

To address the problem, Warinner and colleagues sequenced the nuclear and mitochondrial genomes of eight high-altitude Himalayan individuals dating to three distinct cultural periods spanning 3150 to 1250 years before present.

The authors compared these ancient DNA sequences to genetic data from diverse modern humans, including four Sherpa and two Tibetans from Nepal.

All eight prehistoric individuals across the three time periods were most closely related to contemporary highland East Asian populations, i.e., the Sherpa and Tibetans, strengthening evidence that the diverse material culture of prehistoric Himalayan populations is the result of acculturation or culture diffusion rather than large-scale gene flow or population replacement from outside highland East Asia.

The study broke new ground in other areas as well, yielding the first ancient whole genomes of East Asian ancestry and the highest coverage ancient human genome from Asia (7x coverage) sequenced to date.

The study has been published in Proceedings of the National Academy of Sciences.