Long-term genetic stability and a high-altitude East Asian origin for the peoples of the high valleys of the Himalayan arc

Abstract

in the Sherpa (18), an ethnic group that migrated from the eastern Tibetan plateau to Nepal 400–600 y ago (ya) (19). Tibetans and Sherpa are the only two present-day high-altitude East Asian ethnic groups that have been studied to date, using genome-wide markers. Although the Tibetan plateau has been the subject of intense study regarding its population history and high-altitude adaptation (15, 20–22), far less is known about the much later colonization of the surrounding high transverse valleys along the Himalayan arc. Elucidating this history is important because these valleys have long served as natural corridors and trade routes connecting the Tibetan plateau to the Indian subcontinent. Moreover, the role of adaptation to high-altitude hypoxia in the initial colonization of these valleys and in the subsequent gene flow through them is entirely unexplored. The Annapurna Conservation Area (ACA) of Upper Mustang, Nepal (Fig. 1) is a major high-elevation corridor (2,800–4,500 masl) that includes the earliest known archaeological sites containing preserved human remains in a Himalayan transverse valley (23). Significance Since prehistory, the Himalayan mountain range has presented a formidable barrier to population migration, whereas 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 is known about the region’s peopling and early population history. In this study, we conduct to our knowledge the first ancient DNA investigation of the Himalayan arc and generate genome data for eight individuals ranging in time from the earliest known human settlements to the establishment of the Tibetan Empire. We demonstrate that the region was colonized by East Asians of likely high-altitude origin, followed by millennia of genetic continuity despite marked changes in material culture and mortuary behavior.