Dynamic human admixture histories over the last ~1,300 years at the northern Himalayan frontier

Archaeological and paleogenomic evidence from the Tibetan Plateau and high-altitude Central Himalayas suggest bio-cultural connections with each other and with lowland East, Central, and South Asia. However, genetic histories at the northern frontier of the Indian Himalayas, which is geographically more proximal to Central and lowland South Asia, remain underexplored. We analyzed genome-wide data from seven ancient (~2,300-100 years old) and ten present-day individuals from the northern Indian Himalayas, and one ~3,370-year-old individual from the Central Himalayas in Nepal. Ancient and present-day individuals from the northern Himalayas predominantly have Tibetan-related genetic ancestry, likely the source of high-altitude adaptive variants in these individuals, with substantial Steppe-related genetic ancestry that is observed in all individuals dating between ~1,300 years and present day. Additionally, some present-day individuals have lowland South Asian admixture. Our analyses reveal a dynamic interplay between genetic admixture and continuity in the northern Himalayas.