Molecular Evolution Of Meriones Meridianus

Mid-day gerbil(Meriones meridianus)is a species of rat,which lived in desert,semi-desert of Central Eurasian continent.It distributes in northern China Mongolia,Kazakhstan,rajikistan,Afghanistan,Iran and other East Asian and Central Asian countries and regions.We used polymerase chain reaction(PCR)and direct sequencing methods to infer their molecular evolution based on mitochondrial DNA(mtDNA) control-region data.This study seqenced and analyzed 88 Mid-day gerbils inluding 8 populations,gained 512bp DNA sequence.A total of 75 variable sites defined 56 haplotypes in 88 88 Mid-day gerbils.There were significant differences in nucleotide composition among the population level.Transitions between T and C(54)are much more than transitions between A and G(17),which showed that the differences of nucleotide composition in the Mid-day gerbil were caused by pyridine.Patch habitat could be a barrier to gene exchange,there is no gene flow between Yuzhong population and other populations.Geermu population and other populations have genetic differentiation(P＜0.01),but have gene flow with Dongdashan,Minqin and Shapotou population,respectively.This indicate that Geermu population and this 3 populations had occurred isolated incidents.There was significant negative relationship between geographical distance and the gene flow,and significant positive relationship between geographical distance and the genetic differetial index(Fst).This indicate that geographical distance have influence on intercommunion between populations.There was significant negative relationship between the nucleotide diversity and temperature.According to molecular clock,Yuzhong population and Geermu population divaricated to other populations at 200 thousand years ago.Mismatch distribution analysis indicate Mid-day gerbil population had experienced a population expansion at 15.3 thousand years ago,which validated interglacial have important effect on species expansion.