Ancestral Origins and Genetic History of Tibetan Highlanders
Ancestral Origins and Genetic History of Tibetan Highlanders
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西藏高地人的祖先起源和遗传史
DOI：
10.1016/j.ajhg.2016.07.002
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发表时间：
2016-09-01
影响因子：
9.8
通讯作者：
Xu, Shuhua
中科院分区：
文献类型：
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作者：
Lu, Dongsheng;Lou, Haiyi;Xu, Shuhua
藏人的起源仍然是历史学、人类学和遗传学中最有争议的难题之一。对38名藏族高原人和39名汉族低地人的深度测序（30 - 60倍）基因组的分析，以及关于古代和现代人类的现有数据，使我们能够全面描述藏族人的祖先构成并揭示他们的起源。非现代人类序列占西藏基因库的6%，并在一些基因组区域形成独特的单倍型，其中丹尼索瓦人样，尼安德特人样，古西伯利亚人样和未知祖先纠缠在一起并升高。西藏富集序列的共同祖先可以追溯到62，000 - 38，000年前，早于末次盛冰期（LGM），代表了高原的早期殖民。尽管如此，藏人基因库中的大部分都是现代人类的起源，与15,000年前到9,000年前的汉族人的基因不同，这在很大程度上可以归因于末次冰期后的到来。对200个当代人口的分析显示，藏人与东亚（-82%）、中亚和西伯利亚（11%）、南亚（6%）、欧亚大陆西部和大洋洲（1%）的人口有共同的祖先。我们的研究结果支持藏人起源于多个祖先基因库的混合，但他们的起源比以前怀疑的要复杂和古老得多。我们提供了令人信服的证据，旧石器时代和新石器时代的祖先在西藏的基因库中共存，表明史前高原觅食者和现代西藏人之间的遗传连续性。特别是，高地人基因组中高度分化的序列最有可能是从多个祖先起源的前LGM定居者（SUDER）继承的，并通过自然选择保持高频率。
The origin of Tibetans remains one of the most contentious puzzles in history, anthropology, and genetics. Analyses of deeply sequenced (30x-60x) genomes of 38 Tibetan highlanders and 39 Han Chinese lowlanders, together with available data on archaic and modem humans, allow us to comprehensively characterize the ancestral makeup of Tibetans and uncover their origins. Non-modem human sequences compose-6% of the Tibetan gene pool and form unique haplotypes in some genomic regions, where Denisovan-like, Neanderthal -like, ancient-Siberian-like, and unknown ancestries are entangled and elevated. The shared ancestry of Tibetan-enriched sequences dates back to similar to 62,000-38,000 years ago, predating the Last Glacial Maximum (LGM) and representing early colonization of the plateau. Nonetheless, most of the Tibetan gene pool is of modern human origin and diverged from that of Han Chinese similar to 15,000 to similar to 9,000 years ago, which can be largely attributed to post-LGM arrivals. Analysis of similar to 200 contemporary populations showed that Tibetans share ancestry with populations from East Asia (-82%), Central Asia and Siberia (similar to 11%), South Asia (similar to 6%), and western Eurasia and Oceania (similar to 1%). Our results support that Tibetans arose from a mixture of multiple ancestral gene pools but that their origins are much more complicated and ancient than previously suspected. We provide compelling evidence of the co-existence of Paleolithic and Neolithic ancestries in the Tibetan gene pool, indicating a genetic continuity between pre-historical highland-foragers and presentday Tibetans. In particular, highly differentiated sequences harbored in highlanders' genomes were most likely inherited from pre-LGM settlers of multiple ancestral origins (SUNDer) and maintained in high frequency by natural selection.