Cloning Sequence Analysis Of MHC-DRB Gene Exon 2and Genetic Diversity Study In Bactrian Camel

Objective:This study explores the polymorphisms of MHC-DRB gene of Bactrian camel group in the area of Alxa Right Banner, Alxa Left Banner, Ordos, Bayannur, Xilin Gol League, in Inner Mongolia. Analyzed the correlation of the MHC-DRB gene of the Alxa Bactrian camel and vaginal myiasis disease.Studying the genetic diversity between Alxa Bactrian Camel and Sunit Bactrian Camel and judge genetic relationship of Bactrian camel. In order to provide a important information for disease resistance and breeding of Bactrian camel.Methods:(1) Cloning and sequencing the second exon of MHC-DRB gene of 121 p Bactrian camels from Inner Mongolia, analyzing the sequences, determining the polymorphic site and the type of allele, amino acid mutation site by different analysis software.(2) PCR product direct sequencing techniques were used to test sequence of the second exon of the MHC-DRB gene in 40 p vagina myiasis Alxa Bactrian camels and 54 p healthy Alxa Bactrian camels, calculating the gene frequency and genotype frequency of disease and healthy Camel.(3) PCR product direct sequencing techniques were used to detect polymorphisms of the second exon of MHC-DRB gene in 72 p Alxa Bactrian camel and 25 p Sunit Bactrian Camel, and the genetic diversity parameter values of 97 p Bactrian camels were calculated by analysis software, the phylogenetic tree of two breeds were build by NJ method.Result:(1) Using the analysis software,225 mutation sites and 213 polymorphic sites,36 allelic genes,62 amino acid mutation site were detected.18 putative antigen-binding sites were found in 62 amino acid mutation site. (2) The sequences were analysed from vagina myiasis disease camel and did not suffer vagina myiasis disease camel, both from Alax Bactrian camel,it was found that are controlled by two different genes, healthy camel have three genotypes, disease camel have two genotype. (3) Through the software,72 P Alxa Bactrian camel and 25 P Sunit Bactrian camel sequences were analysed,it was found that three haplotype in Alxa Bactrian camel and two haplotype in Sunit Bactrian camel. (4) The Hardy-Weinberg equilibrium analysis of polymorphic site 93 and 159 revealed that P values are less than 0.05.(5) Tajima Test was carried out for the MHC-DRB gene, Tajima’s D values are positive, P>0.01; (6) The phylogenetic tree were constructed based on the MHC-DRB gene sequences, on which, most of the Alxa Bactrian camel sequences distributed on the same branch of the tree, and most of the Sunit Bactrian camel sequences distributed on the another branch of the tree; seldom sequences from the two breeds distributed on the same branch.Conclusion:MHC-DRB gene shows a large number of polymorphisms among the five areas. Sick of the Alxa camel and healthy of Alxa camel have a certain correlation with MHC-DRB gene. Alxa Bactrian camel have the genetic diversity of the Alxa Bactrian camel and the Sunit Bactrian camel are very ample; the genetic diversity the genetic diversity of sunit Bactrian camel higher than alxa’; the phylogenetic relationship between the two breeds were very close.