| 其他摘要 | The current phylogeographical patterns of small mammal species in the Hengduan Mountains and adjacent areas, south-western China, was shaped by dispersal-vicariance events on the context of frequently orogenetic movements, palaeodrainage basins changes, paleoclimate oscillations and even drastically complex topology. Historically, distinctive genetics discontinuity, population dynamic and structure are formed among roughly north-south ridges and valleys with highly heterogeneous geographical landscape. In the comprehensive perspective, it is an ideal area to investigate genetic differentiation, diversification of species and populations, and adaptation. The Shrew Gymnure (Neotetracus sinensis) is a small mammal species inhibiting moist forests in the Hengduan Mountains and adjacent areas. The exploration of its phylogeny and phylogeography are very important for revealing causes beneath species differentiation and genetic diversity in this area. In this study, markers from two different modes of inheritance were used, including 60 mtDNA data set (12S+ND2+cyt_b), 189 mtDNA cyt_b, 13 nuDNA BRCA1 and 71 nuDNA APOB. Some skills like spatial-temporal phylogeny analysis, three dimensional phylogeography analysis, median-jion network analysis, landscape genetic and population genetic analysis were used to unveil evolutionary relationship and phylogeography and historical population genetics. With regard to evolutionary relationships, Neotetracus is closer to Neohylomys rather than Hylomys. About phylogeography, the N. sinensis in the Hengduan Mountains and adjacent areas were genetically grouped into 3 lineages (western Yunnan, central and southern Yunnan and western Sichuan) and several sub- lineages. Molecular clock showed that evolution of N. sinensis accompanied orogenetic movements, palaeodrainage basins changes, paleoclimate oscillations and Geographic heterogeneity. Based on phylogenetic relationship and genetic distance, we support sub-species status of N. sinensis cuttingi, N. sinensis sinensis and N. sinensis hypolineatus, except that of N. sinensis gongshanensis. However, considering phylogenetic relationship, molecular clock and genetic distance, the independent species status of lineages in western Yunnan, central and southern Yunnan and western Sichuan are are preferred support. Spatial evolution analysis showed that western Yunnan is dispersal center. Three dimensional analysis showed that lineages and sub-lineages are differentiate from west to east, and extent from north to south. Median-jion network indicates that western Sichuan lineage maybe derived south of Sichuan, and western lineage has shared the history of ancestor. Genetic discontinuity among 3 lineages, especially between western Yunnan lineage and central and southern Yunnan lineage, were observed through landscape genetic analysis. Paleodrainage patterns changes were indicated by AMOVA(Analysis of Molecular Variance). Recent population expansion was observed from historical population dynamic analysis, and thus we speculated that western of Gaoligong shan mountain maybe the refugia for N. sinensis in Quaternary glaciation, and second contact was happened to form current distribution range. |
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