Moleculiar Phylogcography Of Himaiayan Snowcock (Tetruogallus Himalayensis)

Himalayan snowcock (Tetraogallus himalayensis) is an endemic species of birds in China belonging to Aves, Galliformes, Phasianidae, Tetraogallus. In this study, the molecular phylogeography of T. himalayensis was studied from11populations across the entire distributional ranges in china based on mitochondrial DNA (D-loop) and microsatellite markers. The aims of this study are to:(1) examine population genetic diversity of the11T. himalayensis populations;(2) reconstruct the phylogeographic relationship of T. himalayensis and detect whether there exists obvious phylogeographic differentiation in this species;(3) compare the phylogeographic structures based on different molecular markers;(4) demonstrate the roles of Pleistocene glaciation and climate oscillation played in the population structure, based on the analyses of genetic differentiation and population demography;(5) detect the effects of hybridization on the genetic diversity of T. himalayensis.In this study, partial mtDNA D-loop sequences (1155bp) of67specimens, and ten microsatellite loci for109specimens from6group were used to analyze the phylogeography of T. himalayensis.The main results include:1. There were significant difference in base composition among11T. himalayensis populations. The value of A+T preponderated over a half of the total base content,which was consistent with mtDNA control-region including abundance A and T.37haplotypes were defined by57variable sites with the mean haplotype diversity and the nucleotide diversity of0.004490.0103±0.00523and0.977±0.0069based on mtDNA D-loop. The average expected and observed heterozygosity was0.857±0.048and0.250±0.271, implying a relatively high genetic diversity of T. himalayensis.2. The Bayesian tree and the haplotype network reveal:all haplotypes were grouped into four clades:clade A (Kunlun Mountains clade), clade B (Northern Qinghai-Tibetan Plateau clade), clade C (Tianshan Mountains clade) and clade D (Kalakunlun Mountains clade). the basal split between clade A and the other three clades occurred in0.291×106years ago, occurred during the period of Mindel-Riss inter-glaciation. Because of the different sample sizes, the results of microsatellites was two big clades and three small clades.3. AMOVA analyses showed a low level of gene flow (Nm=0.62) and significant genetic differentiation (Fst=0.15, P<0.001) among all populations, significant pairwise Fst-values between geographic localities ranged from0.152(DLH-SB) to0.912(PS-TSK). Fst-values were large and significant which indicates restricted gene flow among these populations, and significant pairwise.4. In the phylogenetic tree of snowcock, levels of geographic substructure suggest a recent population division or historically limited gene flow within each group. Two haplotypes (H35and H36) from populations HT and SB are obviously distinct from the others in group A (Kunlun Mountains group), which may be mostly by low levels of gene flow (Nm=0.202) and significant genetic differentiation (Fst=0.711, P<0.001).5. The analysis of mismatch distribution and test of selective neutrality indicated a demographic population expansion. Based on the expansion time, the expansion of Himalayan snowcock occurred in the late Pleistocene with the occurrence of the Wurm glaciation when the climate was cold and dry. Temperatures can drop very low and ice caps. Himalayan snowcock was forced to low altitude for food, so it expanded during glaciation.