The matrilineal ancestry of Nepali populations

Abstract The Tibetan plateau and high mountain ranges of Nepal are one of the challenging geographical regions inhabited by modern humans. While much of the ethnographic and population-based genetic studies were carried out to investigate the Tibetan and Sherpa highlanders, little is known about the demographic processes that enabled the colonization of the hilly areas of Nepal. Thus, the present study aimed to investigate the past demographic events that shaped the extant Nepalese genetic diversity using mitochondrial DNA (mtDNA) variations from ethnic Nepalese groups. We have analyzed mtDNA sequences from 999 Nepalese samples and compared the data with 38,622 published mtDNA sequences from the rest of the world. Our analysis revealed that the genomic landscapes of prehistoric Himalayan settlers of Nepal were similar to the low altitude extant Nepalese (LAN), especially to that of Newar and Magar population group; but differ from contemporary high-altitude Sherpas. LAN might have derived their East Eurasian ancestry mainly from low altitude Tibeto-Burmans, who might have migrated from East Asia and assimilated across the Eastern Himalayas extended from Eastern Nepal to North-East of India, Bhutan, the Tibet and Northern Myanmar. We also identified a clear genetic sub-structure across different ethnic groups of Nepal based on mtDNA haplogroups and ectodysplasin-A receptor (EDAR) gene. Our comprehensive high-resolution mtDNA-based genetic study of Tibeto-Burman communities reconstructs the maternal origins of prehistoric Himalayan populations and sheds light on migration events that have brought most of the East Eurasian ancestry to the present-day Nepalese population.