Laboratory of Molecular Anthropology & Centre for Genome Biology, Dept. of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy.
Department of Human Genetics, University of Chicago, Chicago, United States.
Sci Rep. 2017 Nov 14;7(1):15512. doi: 10.1038/s41598-017-15862-z.
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.
虽然大量的研究关注了使人类能够在青藏高原上扩散的人口过程，但对于喜马拉雅山南麓的最近殖民化过程却知之甚少。特别是，据推测，讲藏缅语的人群的迁移、混合和/或隔离历史非常复杂，并重塑了喜马拉雅弧形两侧的遗传变异模式，但这方面的研究仍只是部分阐明。因此，我们描述了来自尼泊尔偏远山谷的先前未调查过的藏缅语（即夏尔巴人和塔芒人）和印度雅利安社区的基因组景观。对他们与南亚/东亚人群的基因组关系的探索提供了证据，证明藏人曾与低海拔东亚人混合，而夏尔巴人则与外界隔离。我们还表明，其他喜马拉雅山南麓的藏缅人并非来自藏/夏尔巴人血统，而是来自低海拔祖先，这些祖先可能从中国经印度北部/缅甸迁徙而来，经历了广泛的混合，重新排列了祖先的藏缅语基因库。这些发现增进了我们对基因流/漂变对喜马拉雅高海拔人群进化的影响的理解，并阐明了推动喜马拉雅山南麓殖民化的迁移事件，以及不同的藏缅语群体在这种复杂的人口情景中所扮演的角色。
