QIN Zhendong, JIN Li, LI Hui

Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai 200433, China

ABSTRACT:  As a high-altitude immense plateau surrounded by towering mountain ranges, the Tibetan Plateau was once considered to be one of the last populated areas of modern humans. However, this view has been tremendously changed by archaeological, linguistic and genetic findings in the past sixty years. Nevertheless, the time and routes of modern humans into the Tibetan Plateau remain controversial. We sampled 562 Tibeto-Burman inhabitants from nine different regions across the plateau to carry out high-resolution mitochondrial-DNA analyses. By examining the mtDNA haplogroup distributions and their principal components, we demonstrated that the maternal diversity on the plateau reflects mostly the northern East Asian component. Furthermore, phylogeographic analysis of plateau-specific sublineages based on 31 complete sequences revealed two primary components: pre-LGM (Last Glacial Maximum) inhabitants and post-LGM immigrants. Also, the analysis of one major pre-LGM sublineage A10 showed a strong signal of post-LGM population expansion and greater diversity in the southern part of the Tibetan Plateau, indicating the southern plateau as a refuge place when climate dramatically changed during LGM.