Meng,LH (reprint author),Yunnan Normal Univ,Sch Life Sci,Engn Res Ctr Sustainable Dev & Utilizat Biomass E,Minist Educ,Kunming 650092,Yunnan,Peoples R China.
The formation of the Mekong-Salween Divide and climatic oscillations in Pleistocene were the main drivers for the contemporary diversity and genetic structure of plants in the Himalaya-Hengduan Mountains (HHM). To identify the relative roles of the two historical events in shaping population history of plants in HHM, we investigated the phylogeographic pattern of Oxyria sinensis, a perennial plant endemic to the HHM. Sixteen chloroplast haplotypes were identified and were clustered into three phylogenetic clades. The age of the major clades was estimated to be in the Pleistocene, falling into several Pleistocene glacial stages and postdating the formation of the Mekong-Salween Divide. Range expansions occurred at least twice in the early and middle Pleistocene, but the spatial genetic distribution rarely changed since the Last Glacial Maximum. Our results suggest that temporary mountain glaciers may act as barriers in promoting the lineage divergence in Oxyria sinensis and that subsequential range expansions and secondary contacts might reshape the genetic distribution in geography and blur the boundary of population differentiation created in the earlier glacial stages. This study demonstrates that Pleistocene climatic change and mountain glaciers, rather than the Mekong-Salween Divide, play the primary role in shaping the spatial genetic structure of Oxyria sinensis.
1.Yunnan Normal Univ, Sch Life Sci, Engn Res Ctr Sustainable Dev & Utilizat Biomass E, Minist Educ, Kunming 650092, Yunnan, Peoples R China 2.Univ Rhode Isl, Grad Sch Oceanog, Kingston, RI 02881 USA 3.NW Univ Xian, Coll Life Sci, Key Lab Resource Biol & Biotechnol Western China, Minist Educ, Xian 710069, Shanxi, Peoples R China 4.Chinese Acad Sci, Kunming Inst Bot, Kunming 650204, Yunnan, Peoples R China 5.Duke Univ, Dept Biol, Durham, NC 27708 USA