被誉为“世界屋脊”的青藏高原环境恶劣，是人类较难以生存适应的地区。但青藏高原上仍发掘出了较多旧石器，表明该区域旧石器时期可能已经有人类居住。从考古资料来看，青藏高原上最主要的石器——细石器，既有华北细石器的特点，也承袭了一些当地旧石器的特征，提示新石器时期的青藏高原人类很可能接受了当地旧石器人类的文化上甚至遗传上的影响。
为系统研究藏族人群的起源，在张亚平院士带领下，博士生赵勉和孔庆鹏研究员等采集了覆盖藏族在中国所有主要聚居地（西藏、青海、甘肃、四川及云南）的大量藏族人群样本并对其母系遗传结构进行详尽解析。结果表明，现代藏族人98％左右的母系遗传组份均可追溯至新石器时期以来迁入青藏高原的中国北方人群，这与之前的遗传研究结果及历史记载相一致。但值得注意的是，研究也发现了一种稀有遗传组份（类群M16）。与源自中国北方人群的母系遗传组份不同的是，M16直接从欧亚大陆建群类群M分化而来，基本只能在藏族群体中观测得到，且具有非常古老的分化年龄（>2.1万年）。对该结果最合理的解释是，M16很可能代表了旧石器晚期即已定居青藏高原的现代人类祖先延续至今的母系遗传组份。
该研究提示，现代人类祖先在旧石器晚期即已克服恶劣的气候及地理条件，成功定居于青藏高原，因而很好地解决了长期以来考古学、历史学及遗传学领域关于“人类最早何时成功定居于青藏高原”的争论。同时也从遗传上进一步证实，现今绝大多数藏族事实上源自新石器时期以来迁入青藏地区的中国北方人群。
研究结果近期发表在PNAS（《美国科学院院刊》）上。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS December 2, 2009, doi: 10.1073/pnas.0907844106
Mitochondrial genome evidence reveals successful Late Paleolithic settlement on the Tibetan Plateau
Mian Zhaoa,b,1, Qing-Peng Konga,c,1,2, Hua-Wei Wangd, Min-Sheng Penga,b, Xiao-Dong Xiee, Wen-Zhi Wanga,b, Jiayangf, Jian-Guo Duang, Ming-Cui Caih, Shi-Neng Zhaoh, Cidanpingcuoi, Yuan-Quan Tuj, Shi-Fang Wua, Yong-Gang Yaok, Hans-Jürgen Bandeltl and Ya-Ping Zhanga,c,d,2
aState Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan Province, China;
bGraduate School of the Chinese Academy of Sciences, Beijing 100049, China;
cKIZ/CUHK, Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming 650223, China;
dLaboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming 650091, Yunnan Province, China;
eKey Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Science, Lanzhou University, Lanzhou 730000, Gansu Province, China;
fClinical Laboratory, People's Hospital of Shigatse Prefecture, Shigatse 857000, Tibet Autonomous Region, China;
gClinical Laboratory, People's Hospital of Nakchu Prefecture, Nakchu 852000, Tibet Autonomous Region, China;
hBlood Center of Liangshan Yi Autonomous Prefecture, Xichang 615000, Sichuan Province, China;
iBlood Center of Tibet, Lhasa 850000, Tibet Autonomous Region, China;
jYunnan Kunming Blood Center, Kunming 650106, Yunnan Province, China;
kKey Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; and
lDepartment of Mathematics, University of Hamburg, 20146 Hamburg, Germany
Due to its numerous environmental extremes, the Tibetan Plateau—the world's highest plateau—is one of the most challenging areas of modern human settlement. Archaeological evidence dates the earliest settlement on the plateau to the Late Paleolithic, while previous genetic studies have traced the colonization event(s) to no earlier than the Neolithic. To explore whether the genetic continuity on the plateau has an exclusively Neolithic time depth, we studied mitochondrial DNA (mtDNA) genome variation within 6 regional Tibetan populations sampled from Tibet and neighboring areas. Our results confirm that the vast majority of Tibetan matrilineal components can trace their ancestry to Epipaleolithic and Neolithic immigrants from northern China during the mid-Holocene. Significantly, we also identified an infrequent novel haplogroup, M16, that branched off directly from the Eurasian M founder type. Its nearly exclusive distribution in Tibetan populations and ancient age (>21 kya) suggest that M16 may represent the genetic relics of the Late Paleolithic inhabitants on the plateau. This partial genetic continuity between the Paleolithic inhabitants and the contemporary Tibetan populations bridges the results and inferences from archaeology, history, and genetics.
