Genetic Diversity Of TLR2 Gene In Chinese House Mice (Mus Musculus)

House mice(Mus musculus)are belonging to Mammalia,Rodentia,Muridae,Mus.It is a kind of human commensals that distribute all over the world.House mice are the ancestors of experimental mice that the most widely used in the world,and it's the main animal source of infection and host animals.It's was widely used in ecological,evolutionary and genetic studies.TLR2 gene has important functions in individual innate immune response,it can be better to understand different species of the natural environment adaptation mechanism that study the genetic evolution characteristics.Further investigate of TLR2 gene is not only of great theoretical significance,but also of great practical significance.In this research,we made experiments to get DNA of Mus musculus,and we did PCR amplification and sequencing to get TLR2 sequence of 295 samples of M.musculus.The genetic characteristics,population genetic structure and phylogeny of 295 M.musculus samples from 26 geographical populations were analyzed by molecular markers of M.musculus.In the study of the genetic diversity of M.musculus,the average content of base composition A,T,C and G was 27.5%,26.2%,22.9% and 23.3%,respectively,in the 26 geographic populations of M.musculus TLR2 gene fragment(692 bp),and showed preference for A + T,which led to the higher A + T content(53.7%).There were 47 variation sites(V)which include 37 Singleton variable sites(S)and 10 Parsimony informative sites(Pi),that indicated the genetic diversity of M.musculus in China was low.To do the neutrality test of the TLR2 sequences of 295 M.musculus,the value of Tajima's D was-2.54680,P < 0.01,the difference was very significant.A total of 30 haplotypes were identified among the 295 individuals.Of these haplotypes,25 were in a single individual,5 were shared among individuals within populations.Haplotype H1 comprised the number of samples was 203 distribute into 26 populations,accounting for 68.81%,Haplotype diversity(Hd)was 0.5113,and Nucleotide diversity(Pi)was 0.00151.The 23 populations which were more than 5 samples were studyed for molecular phylogeny.We did the analysis of genetic diversity of 23 geographic populations,the highest value of nucleotide diversity(Pi)was in GX(Guangxi Nanning),Pi = 0.01135,which the lowest was in WN(Weinan),Pi = 0.00050,the average of Pi was 0.00390;the highest value of nucleotide diversity(K)was in GX(Guangxi Nanning),K = 7.60714,which the lowest was in WN(Weinan),K = 0.33333,and the average value of(K)is 2.61206.Haplotype analysis was carried out on 23 geographic populations,The highest haplotype diversity was in W(Wuhan),Hd was 0.933,the lowest haplotype diversity was in XJ(Xinjiang),and Hd was 0.167.The number of variation sites(S)of the TLR2 gene in each geographic population was different,the ranging was 2(Weinan)to 28(Kunming).To do the neutrality test of the TLR2 sequences of 23 geographical populations,there were nine positive value of Tajima's D in nine populations(A(Anyang)CY(Chaoyang)CZ(Changzhi)GD(Guangdong)GZ(Guizhou)MH(Mohe County)PX(Pingxiang)SP(Siping)TW(Taiwan))of M.musculus,and the value of other 13 areas were negative.We calculated the genetic diversity between the 23 loci populations,and the value of genetic diversity coefficient of the TLR2 gene was between 0.0000 and 0.00876.The highest value was 0.00876 between KM(Kunming)and MH(Mohe).The highest value of nucleotide divergence(Dxy)among geographical populations was 0.00965 that was between GX(Guangxi)and TW(Taiwan),the lowest was value of nucleotide divergence(Dxy)among geographical populations was YT(Yantai)with WN(Weinan),WN(Weinan)with SY(Songyuan),and Dxy was 0.000025.The 23 geographical populations showed a large genetic similarity,which was caused by gene flow among populations.The 30 haplotypes defined by all 26 geographic populations are generally divided into one group without obvious clusters.The results showed that the genetic differentiation rate of TLR2 gene was low,the population was relatively stable,and the difference was not significant,and there was no obvious population differentiation and geographical isolation.