Environmental Correlates Of Genetic And Phenotypic Differentiation Of The Qinghai Sand Lizard

Prynocephalus vlangalii has the largest distribution area and vertical span on the Qinghai-Tibet Plateau,and it is also the dominant lizard species in its distribution area.The huge environmental differences may lead to the genetic,morphological,physiological and reproductive differences among populations of the lizard.Mitochondrial DNA sequences,morphology,reproduction and metabolism data of 9wild populations were analyzed in this study.The genetic and phenotypic variations among populations were studied in combination with habitat climate factors to explore the causes of these differentiation.The main results are as follows:1.Genetic differentiation of 147 individuals from 9 populations was studied based on three mitochondrial genes(16S,ND2 and ND4)and a strong population genetic differentiation was found due to geographical isolation.Population history dynamics and neutral test showed that each clade of the lizard was relatively stable.2.The correlation between genetic distance(GEN),geographical distance(DIS),environmental distance(ENV)and elevation distance(ELE)was analyzed by Mantel test.It was found that there was a weak correlation among the three matrices,indicating that genetic differentiation was a combination of many effects.Comparing P_ST/F_ST values for 12 morphological variables,we found that P_ST was greater than F_STfor snout-vent length and smaller than F_STfor the other 11 morphological phenotypes.These results provide support for stabilizing selection driving morphological differentiation in P.vlangalii but it could also be explained by environment-mediated phenotypic plasticity.3.Phenotypic differentiation was significant among populations of P.vlangalii.Principal components analysis(PCA)of morphological variables showed that except for fore-limb length and tail length,the remaining morphological variables all contributed higher loadings for the morphological differentiation between populations.The results of principal component correlation analysis of climate factors and morphological variables were not significant,which was consistent with the results of Mantel test which found no significant correlation between phenotypic distance(PHE)and geographical distance(DIS),environmental distance(ENV),genetic distance(Gen)and altitude distance(ELE)matrix.In addition,the redundancy analysis(RDA)showed that the morphological variables were positively correlated with the Bio3(Isothermality),and negatively correlated with Bio2(Mean Diurnal Range)and Bio15(Precipitation Seasonality).Bio1(Annual Mean Temperature),Bio3(Isothermality)and Bio11(Mean Temperature of Coldest Quarter)were the key climatic factors affecting the main morphological variables.4.Geographical differences in reproductive characteristics of P.vlangalii were not only the result of lineage dependence,but also the response to local adaptation to heterogeneous habitats.The resting metabolic rate per unit body weight increased with the increase of body weight,and there were significant differences among populations.Based on the phylogenetic generalized least square method,no significant correlation was found between the maintenance energy consumption and reproductive output,indicating that reproductive output was almost unaffected by the level of maintenance energy consumption.