Outside The Black Line Hamster Dqa And Drb Exon 2 Polymorphism And Population Genetic Structure

The Chinese Striped Hamster (Cricetulus barabensis) can be harmful rodents, damaging and eating crops, and spreading diseases through their parasites and feces. It is distributed across Northern Asia, from southern Siberia through Mongolia to northeastern China. The major histocompatibility complex (MHC) region of vertebrates is a highly polymorphic genomic region with an important role in the regulation of the immune system. MHC variability reflects evolutionary relevant and adaptive processes within and between populations. So it is suitable to investigate questions in population structure and evolutionary ecology.In the presented research, sequence variability at exon 2 of two Class II genes (DQA and DRB) were investigated in 3 geographic populations of Shandong Province., including population genetics information on sequence variation examined in 74 Chinese Striped Hamster samples, and genetic diversity examined in 55 clone samples. Our research expected to have an in-depth understanding on the molecules-level, especially the reason of evolution caused by selection pressure. This study will provide basis for population genetics and periodic outbreak by evolution relationships observed firstly among variabilty of MHC II class genes, The population genetic structure of the Chinese Striped Hamster was studied by using liver tissue collected around Shandong province from March to October 2006. This study used DQA*exon 2 of MHC II class gene as molecular marker to analyze the genetic diversity and population genetic structure for different groups in Shandong province. A total of 74 sampled from 3 sampled areas (Linqu, Qufu, Yinan) were surveyed by using the DQA*exon 2(249 bp in length), which yielded a total of 16 haplotypes with a mean nucleotide diversity (Pi) of 0.0004 and haplotype diversity (Hd) of 0.757±0.041. Nucleotide variance types of Crba-DQA were all transition and transversion. None insert/deletion was detected at exon 2 of Crba-DQA. It is almost transition and coden variation of first and second was more than the third coden. Sequence NJ-tree showed that different haplotypes did not grouped together by sample areas, suggesting some identical alleles were shared in the all samples. No significant population subdivisions were detected by AMOVA (Fixation Indices= 0.0515, p>0.05). FST and Nm indicated that Chinese Striped Hamster around Shandong is highly exchanging status, except between Yinan and Qufu areas. The Crba-DQA exon2 were not in neutral equilibrium in any sample areas group, so it would be the forces of positive selection acted to maintain similar alleles as indicated by relatively high rates of nonsynonymous (dN) vs. synonymous (ds) substitution.Other 11 individuals (53 clone sample) from Yinan were surveyed by using the DRB* exon 2 (190 bp in length), which yielded a total of 22 haplotypes with a mean nucleotide diversity (Pi) of 0.0004 and haplotype diversity (Hd) of 0.757±0.041. Evolution trees between different breeds were constructed through BLAST homologous search at DRB loci, the results showed that rodents, primates, even-toedungulates were clustered together respectively.