Tagore Debashree, Majumder Partha P, Chatterjee Anupam, Basu Analabha
National Institute of Biomedical Genomics, Kalyani, India.
Indian Statistical Institute, Kolkata, India.
Front Genet. 2022 Oct 11;13:1023870. doi: 10.3389/fgene.2022.1023870. eCollection 2022.
NorthEast India, with its unique geographic location in the midst of the Himalayas and Bay of Bengal, has served as a passage for the movement of modern humans across the Indian subcontinent and East/Southeast Asia. In this study we look into the population genetics of a unique population called the Khasi, speaking a language (also known as the Khasi language) belonging to the Austroasiatic language family and residing amidst the Tibeto-Burman speakers as an isolated population. The Khasi language belongs to one of the three major broad classifications or phyla of the Austroasiatic language and the speakers of the three sub-groups are separated from each other by large geographical distances. The Khasi speakers are separated from their nearest Austroasiatic language-speaking sub-groups: the "Mundari" sub-family from East and peninsular India and the "Mon-Khmers" in Mainland Southeast Asia. We found the Khasi population to be genetically distinct from other Austroasiatic speakers, i.e. Mundaris and Mon-Khmers, but relatively similar to the geographically proximal Tibeto Burmans. The possible reasons for this genetic-linguistic discordance lie in the admixture history of different migration events that originated from East Asia and proceeded possibly towards Southeast Asia. We found at least two distinct migration events from East Asia. While the ancestors of today's Tibeto-Burman speakers were affected by both, the ancestors of Khasis were insulated from the second migration event. Correlating the linguistic similarity of Tibeto-Burman and Sino-Tibetan languages of today's East Asians, we infer that the second wave of migration resulted in a linguistic transition while the Khasis could preserve their linguistic identity.
印度东北部位于喜马拉雅山脉和孟加拉湾之间，地理位置独特，一直是现代人类穿越印度次大陆以及东亚/东南亚的通道。在本研究中，我们探究了一个独特群体——卡西族的群体遗传学。卡西族说一种属于南亚语系的语言（也称为卡西语），作为一个孤立群体生活在说藏缅语的人群之中。卡西语属于南亚语系三大主要分类或语族之一，三个亚群体的使用者被巨大的地理距离分隔开来。说卡西语的人群与距离他们最近的说南亚语系语言的亚群体分隔开来：来自印度东部和半岛地区的“蒙达里”语族，以及东南亚大陆的“孟高棉”语族。我们发现卡西人群在基因上与其他说南亚语系语言的人群（即蒙达里人和孟高棉人）不同，但与地理位置相近的藏缅人相对相似。这种基因 - 语言不一致的可能原因在于不同迁移事件的混合历史，这些迁移事件起源于东亚，可能朝着东南亚发展。我们发现至少有两次来自东亚的不同迁移事件。虽然如今说藏缅语的人群的祖先受到了这两次迁移事件的影响，但卡西人的祖先与第二次迁移事件隔绝。结合当今东亚人藏缅语和汉藏语的语言相似性，我们推断第二次迁移浪潮导致了语言转变，而卡西人能够保留他们的语言特征。
