The genomic landscape of Nepalese Tibeto-Burmans reveals new insights into the recent peopling of Southern Himalayas

Abstract

While much research attention has focused on demographic processes that enabled human diffusion on the Tibetan plateau, little is known about more recent colonization of Southern Himalayas. In particular, the history of migrations, admixture and/or isolation of populations speaking Tibeto-Burman languages, which is supposed to be quite complex and to have reshaped patterns of genetic variation on both sides of the Himalayan arc, remains only partially elucidated. We thus described the genomic landscape of previously unsurveyed Tibeto-Burman (i.e. Sherpa and Tamang) and Indo-Aryan communities from remote Nepalese valleys. Exploration of their genomic relationships with South/East Asian populations provided evidence for Tibetan admixture with low-altitude East Asians and for Sherpa isolation. We also showed that the other Southern Himalayan Tibeto-Burmans derived East Asian ancestry not from the Tibetan/Sherpa lineage, but from low-altitude ancestors who migrated from China plausibly across Northern India/Myanmar, having experienced extensive admixture that reshuffled the ancestral Tibeto-Burman gene pool. These findings improved the understanding of the impact of gene flow/drift on the evolution of high-altitude Himalayan peoples and shed light on migration events that drove colonization of the southern Himalayan slopes, as well as on the role played by different Tibeto-Burman groups in such a complex demographic scenario.

Evidence of polygenic adaptation to high altitude from Tibetan and Sherpa genomes

“…A Sherpa individual from the Rolwaling Himal (Gaurishankar Conservation Area, GCA, Dolakha District, Nepal), who was third-generation native of the Rolwaling Sherpa community (i.e., with both parents and grandparents born in the village of Beding at 3,690 m a.s.l. ), was chosen among those recruited during several sampling campaigns ( Gnecchi-Ruscone et al. 2017 ) organized in collaboration with the ExPlora Nunaat International nonprofit organization.…”

“…2017 ) organized in collaboration with the ExPlora Nunaat International nonprofit organization. This subject was selected to be representative of the Rolwaling Sherpa population, presenting 100% of the “Sherpa-like” genetic component observed in previous studies ( Gnecchi-Ruscone et al. 2017 ) and a high-altitude adapted phenotype (i.e., he is a professional mountaineer and Himalayan Guide who have climbed Mount Everest several times).…”

Investigating the likely association between genetic ancestry and COVID-19 manifestations

“…Notably, the South Asian population(s) with whom the incoming Southeast Asians mingled were AASI related with little to no West Eurasian ancestry fraction [27]. Finally, it has been showed that the Tibeto-Burmans (ATBs) derived their ancestry through admixture with low-altitude East Asians who migrated from China and likely across Northern India or Myanmar [28] leading to the high genomic proximity between South Asians of ATB ancestry and East Asians.…”

Back-of-the-Envelope Guide (A Tutorial) to 10 Intracellular Landscapes

“…Hence, mutational landscape often refers to sequence variations leading to diseases; such as, with reference to cancer. [19][20][21] On the other hand, nucleotide sequence variations consistent with positive impressions; such as with respect to adaptation 22 and tolerance; 23,24 or neutral impressions such as allelic variations within species; [25][26][27][28] tends to be referred to as genomic landscape. However, the opposite may also be true as mutational landscape had also been used to describe natural variations between species.…”

“…32 The essential genes in B. breve include (a) housekeeping genes; such as, DNA replication and transcription, manufacture of cell envelope components, the Secdependent protein translocation pathway; (b) genes in central pathways for energy acquisition and conversion; such as central glycolysis, a specific bifid-shunt, pentose phosphate pathway, and pathways crucial for production of energy and precursors for other metabolic routes; (c) genes encoding subunits of ATP synthase; (d) genes encoding enzymes involved in purine and pyrimidine synthesis; and (e) genes encoding proteins involved in ion transport and redox homeostasis. Lastly, Gnecchi-Ruscone et al, 25 successfully genotyped 59 buccal swab from 4 communities near the Tibetan plateaus. By analyzing the SNPs, a model to describe the migration and colonization of Southern Himalayan slopes from East Asia ancestry is proposed.…”