Phylogeography And Genetic Structure Of The Phrynocephalus Axillaris In The Tarim Basin And Surrounding Areas

Phrynocephalus axillaris belongs to the genus Phrynocephalus of the family Agamida and is an endemic species in China.The phylogeographic structure and evolutionary history of the P.axillaris are not clear and need to be supplemented by further studies.Therefore,in this paper,we use three molecular markers(mt DNA,nuclear genes and SNP)to study the gene flow,genetic differences and genetic structure among the 239 samples from Xinjiang,and to determine the genealogical structure and speculate on the time of genealogical divergence in order to explore the geographical distribution pattern of these 21 populations.The main objectives of the study were:(1)to assess interpopulation gene flow and genetic variation;(2)to analyse the genetic structure of the populations and investigate the influence of climatic data on genetic structure;and(3)to analyse the geographical structure of the lineages and elucidate the relationship between genealogical differentiation and environmental evolution.The results were as follows:(1)haplotype diversity and nucleotide diversity were calculated for 21 geographical populations based on nuclear genes,with results showing 0.333(YJS)-1.000(ARZ),0.00028(TKX)-0.00468(ATS),respectively;results based on mitochondrial genes showed 0.744(TKX)-1.000(YJS),0.00064(TKX)-0.01214(YJS).Influenced by the uplift of the mountain range and the ice age,the population of P.axillaris first began to differentiate into two clades at around 3.23 Ma,while the complete differentiation of each geographical population was really around 1.00 Ma,with obvious genetic differences between populations.(2)Genetic distance trees,fast Structure structural cluster analysis and discriminant principal component analysis(DAPC)based on SNP data showed significant genetic structure among P.axillaris populations in the 21 sampling areas,with two populations,TKX and WS,being significantly different from other populations and the KEL population having a high degree of admixture,further suggesting that the study of P.axillaris population in this region is a good example of genetic differentiation.The level of gene flow between populations of P.axillaris in this region is low,and the dispersal and migration of individuals may be mainly restricted to within populations.(3)The results of the neutrality test and mismatch distribution indicate that the population has not historically undergone rapid expansion,which may be related to the environment in which it is located,and the RDA results further validate the important influence that environmental temperature may have on the genetic structure and adaptive genetic variation of the P.axillaris.This paper explores the effects of environmental change on the evolutionary process and genetic diversity of P.axillaris in the context of its population genetic structure and phylogeographic pattern,which can further understand the formation mechanism of P.axillaris population and provide basic materials for the genetic conservation of this species,as well as provide important theoretical support for the conservation and management of biodiversity in desert ecosystems.