Origins, Population Genetics And Comparative Phylogeography Of Two Lacertid Lizards (Eremias Argus And E.Brenchleyi) From China

Eremias argus and E. brenchleyi are lacertid lizards that are sympatric throughout the distribution of E. brenchleyi. We sequenced partial mitochondrial DNA from cytochrome (cyt) b gene for 106 individuals of E. argus from nine localities, and for 45 individuals of E. brenchleyi from five localities, in central and northern parts of North China. We determined 53 cyt b haplotypes from the E. argus samples, and 27 cyt b haplotypes from the E. brenchleyi samples. Only E. brenchleyi had followed a stepping-stone model of dispersal. Partitioned Bayesian phylogenetic analysis reveals that E. argus and E. brenchleyi are reciprocally monophyletic, and the divergence time between the two species was dated to about 4.1±1.2 million years ago. Geographical structuring of haplotype is more significant in E. brenchleyi than in E. argus. Haplotypes of E. brenchleyi could be divided into four groups by the Yellow River and Taihang Mountains. Within-population genetic diversity indices are correlated neither with latitude nor with longitude. We calculated significant among-population structure for both species (E. argus:φST=0.608, P<0.001; E. brenchleyi:φST=0.925, P<0.001). Eremias brenchleyi has four independent management units, while E. argus has a more homogeneous genetic structure across its range. Our data show that:(1) the pattern seen in North American and European species that southern populations have higher genetic diversity as consequence of post-glaciation dispersal is absent in the two Chinese lizards; (2) the Yellow River and Taihang Mountains may have acted as important barriers to gene flow only in E. brenchleyi; and (3) genetic structure differs between the two lizards that differ in habitat preference and dispersal ability.We sequenced partial mitochondrial DNA from ND4 gene for 128 individuals of Eremias argus from nine localities, and for 46 individuals of E. brenchleyi from five localities, in central and northern parts of North China. We determined 44 cyt b haplotypes from the E. argus samples, and 33 cyt b haplotypes from the E. brenchleyi samples. Only E. brenchleyi had followed a stepping-stone model of dispersal. Partitioned Bayesian phylogenetic analysis reveals that E. argus and E. brenchlcyi are reciprocally monophyletic. Geographical structuring of haplotype is more significant in E. brenchleyi than in E. argus. Haplotypes of E. brenchleyi could be divided into four groups by the Yellow River and Taihang Mountains. Within-population genetic diversity indices are not correlated with latitude. We calculated significant among-population structure for both species (E. argus:φST=0.594, P<0.001; E. brenchleyi:φSt=0.908, P<0.001). We used also partial mtDNA sequences for 16S gene to infer pathways for the two lizards to colonize Eastern Asian, and determine if oviparity represents the ancestral mode of reproduction in Eremias. Our data show that:(1) viviparous species has evolved from oviparous species in eight Eremias species in China; (2) Both E. argus and E. brenchleyi originated from Central Asia; (3) There were multiple refugia across their species range identified in the two Chinese lizards; and (4) the demographic history of E. brenchleyi shows a long-lasting population decline since time of the most recent common ancestor (MRC A), while E. argus mainly show continuous population growth since time of the MRCA.We sequenced partial mitochondrial DNA from cytochrome (cyt) b gene for 180 individuals of E. argus from sixteen localities in central and northern parts of North China. We determined 80 cyt b haplotypes from the E. argus samples. Within-population genetic diversity indices are not correlated with latitude. We calculated significant among-population structure for this species (φST=0.683, P< 0.001). Our data show that:(1) the Yellow River, Qinling and Taihang Mountains may not have acted as important barriers to gene flow in E. arugs; (2) we identified refugia in the Manchurian Plain, lower reaches of Yangtze River, Kuan-Chung Plain, east edge of Loess Plateau, and Ortos Plateau; (3) Some potential migration-routes are identified within refugia; (4) the demographic history of E. argus mainly show continuous population growth since time of the most recent common ancestor.