| Clusters of mountains in which environmental conditions at higher elevations differ markedly from those in the lower elevations valleys,causing the heterogeneity of different altitudinal zones,and resulting in the geographical isolation of alpine organisms,which lead to changes in their morphology and genetic structure,this clusters of mountains,also known as sky islands.The landform of sky island in southwest China is very complex,maximum altitude difference is more than 7000 m,the climate and habitat differences with different altitudes,and all of these result in the diversity of species in this area.However,the ecological and evolutionary mechanisms behind the diversity of species remain unclear.Meanwhile,the global climate has a great fluctuation in the past three million years,leading to several glacial periods in history,an inescapable consequence for most living organisms is great changes in their distribution.In particular,the climatic cycles between Pleistocene glaciation and interglacial period,to some extent,affected the population genetic structure,species and population distribution pattern.The research for Hemiphyllodactylus in China is mainly concentrated on the molecular systems,the effects of global climate change and Pleistocene climate cycles on the biogeographical patterns of Hemiphyllodactylus is still unclear.Because of its unique habitat characteristics,sky island is of great significance to understand the effects of Pleistocene climatic cycles on species distribution and genetic diversity.Therefore,the Hemiphyllodactylus in Yunnan Guizhou plateau area are material in our study,combined with two genetic markers of mitochondrial and microsatellite,we investigated the phylogeographic pattern of Hemiphyllodactylus in China.We screened 24 polymorphic microsatellite loci in H.yunnanensis,and the cross species amplification in 6 species of Hemiphyllodactylus in China was successful.Application of screened 20 non-linkage disequilibrium microsatellite loci,we genotyped 20 populations of Hemiphyllodactylus from Yunnan Guizhou plateau,and combined with the 312 sequences of mitochondrial ND2 gene,we analyzed the genetic diversity,population genetic structure,gene flow,population demography and divergence of Hemiphyllodactylus,in order to reveal the influence on genetic differentiation and geographical distribution pattern of Hemiphyllodactylus caused by unique habitat characteristics in sky island and climate change in geologic time.We obtain the following conclusions by the results of two kinds of molecular markers(mitochondria and microsatellites DNA):(1)The species of Hemiphyllodactylus in Yunnan Guizhou plateau have great genetic differences and fewer gene exchanges,we speculate that it is due to the geographical isolation in different altitudinal zones caused by the unique habitat environment in sky island.Meanwhile,this allopatric differentiation pattern also makes Hemiphyllodactylus accumulate high genetic diversity.(2)The genetic structure and the existing divergence in each branch of Hemiphyllodactylus,we speculate that it is influenced by the Himalaya orogeny during the Miocene,neotectonic movement in China,the uplift of Yunnan Guizhou plateau,climate cycles in Pleistocene and the unique habitat characteristics in sky islands.However,the populations of southern and western areas of Yunnan Guizhou plateau are mixed with genetic information respectively based on the results of the microsatellite markers,we speculate that it is caused by migration and gene flow in different populations,then in the process of genetic drift,the allele was retained subsequently.(3)The population demography and distribution pattern are affected by the Dali glaciation in Pleistocene.In addition,We also reconstructed ancestral distribution according to the 27 ND2 gene sequence of Hemiphyllodactylus from domestic and foreign,and speculate that Hemiphyllodactylus is most likely originated in Malaysia and then spread outwards. |
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