青藏高原史前人类定居与迁徙模式的遗传学研究

Tibetan Plateau represents one of the most extremes of human settlement environment due to its high-altitude hypoxic stress. Currently there are nearly 5 million indigenous Tibetans residing on the Plateau, however, the chronological profiles such as when modern humans first permanently settled on the Tibetan Plateau and the subsequent episodes of human migrations and their demographic history, as well as the modes of diffusion of Neolithic agriculture into the Plateau remain unknown. Recently, we conducted a large scale phylogeographic analysis for 6,109 Tibetan samples from 40 geographic populations in the southern part of the Qinghai-Tibetan Plateau (QTP) using Y-chromosome and mitochondrial (mtDNA) genome markers, and this is a continuity of this project aiming to further recruit another 27 Tibetan populations from the northern QTP (i.e., Qinghai Province), and peripheral QTP areas. By systematically analyzing the phylogeographic patterns of Y-chromosomal and mtDNA haplogroups on the entire region of the QTP, we intend to identify Tibetan-specific ancient Y-chromosomal and mtDNA haplogroups, and reconstruct demographic history of modern human populations through time during the past 40,000 years ago. The objectives of this project are to tackle the following key scientific questions from genetic perspectives such as when the ancestors of modern Tibetans first permanently settled on the QTP and the pattern of human migrations and their demographic dynamics through time, as well as how the Neolithic agriculture diffused into the QTP and their impact on genetic diversity of modern Tibetan populations. The findings will be informative and have important scientific values in studies on archaeology, anthropology, origins of agriculture and pastoralism as well as mechanism of genetic adaptation to high-altitude hypoxia on the QTP.

青藏高原是人类居住的最极端环境之一，目前居住有近500万藏族居民。然而，现代人类是何时开始在青藏高原永久定居，以及随后的人群迁徙过程等史前历史还不清楚。本项目拟在我们最近对覆盖整个青藏高原南部区域（西藏全区）的40个藏族人群（n=6,109）的Y-染色体和mtDNA谱系地理学分析基础上，补充青藏高原北部区域（青海）及高原周边藏族聚居区的27个藏族人群。然后通过系统分析整个青藏高原藏族人群的Y-染色体和mtDNA单倍型类群的谱系地理学格局以及青藏高原近4万年以来的人群动态变化历史，旨在从遗传学角度回答"（1）现代人类是何时开始向青藏高原迁徙并实现永久定居的？（2）现代人类在青藏高原的迁徙历史和群体动态变化过程？（3）新石器农业在青藏高原的扩张模式及其对现代藏族人群遗传多样性格局形成的影响"等关键科学问题。研究结果对青藏高原的考古学、人类学和农牧业起源及高原适应机制等研究具有重要的科学价值。

本项目的研究目标是拟在前期对覆盖整个青藏高原南部区域（西藏全区）的40个藏族人群（n=6,109）的Y-染色体和mtDNA谱系地理学分析基础上，补充青藏高原北部区域（青海）及高原周边藏族聚居区的27个藏族人群。然后通过系统分析整个青藏高原藏族人群的Y-染色体和mtDNA单倍型类群的谱系地理学格局以及青藏高原近4万年以来的人群动态变化历史，最终的研究目标是从遗传学角度回答“现代人类是何时开始永久定居青藏高原及其随后的人群迁徙过程和群体动态变化历史以及新石器农业在青藏高原的扩张模式及其对现代藏族人群遗传多样性格局形成的遗传贡献”等关键科学问题，为青藏高原的考古学、人类学和农牧业起源以及高原低氧适应的分子机制等研究提供遗传学的证据。本项目按计划完成全部的研究任务，达到预期目标。补充采集了38个地理群体的7550人的血液DNA样本，包括覆盖整个青藏高原北部（青海全省）及其周边地区（四川省甘孜藏族自治州、阿坝藏族自治州）的29个藏族地理群体的6782人以及其它常居青海省的汉族、回族、蒙古族等9个地理群体的768人。建立了利用PCR扩增产物的二代测序技术获得mtDNA全长序列的技术平台，并完成对覆盖整个青藏高原地区20个代表性地理人群的1900人的mtDNA的全基因组序列数据，正在进行mtDNA序列的拼接与遗传学分析，研究结果预期在2018年内发表。另外，在“东亚人群史前定居与迁徙历史”、“东亚人群对环境因素适应性进化的分子机制”等研究中取得了一批原创性成果。发表研究论文7篇，在生命百科全书发表特邀综述文章1篇。培养博士研究生4人，承办地区学术会议1次，6人次参加国际学术会议。获西藏自治区科技奖二等奖1项（第五完成人）。

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