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Muntjacs known for its unique chromosomal composition and karyotype evolution mechanism, ideal object of study mammalian karyotype evolution mechanism. MHC genes are vertebrate specific immune response is closely related to a class of multi-gene family. A large number of studies have shown that MHC genes polymorphisms affected by some form of balancing selection, and therefore is considered to be the best candidate markers to study mechanisms of adaptive evolution in spine research animals. MHC gene polymorphism and its evolution mechanism of evolutionary genetics and molecular ecology research focus, so far, is still a lack of in Cervidae Mhc-DRB gene evolution mechanism from the muntjac subfamily animal study evidence. Muntjacs the black muntjac animals (Muntiacus crinifrons) and study the muntjac (Muntiacus reevesi) in the chromosome composition, the karyotype characteristics, population evolutionary history, geographic distribution and population status and so there are significant differences, Both explore the animal DRB gene polymorphism and its evolution mechanism Muntiacus the one hand, the results provide evidence from muntjacs, the Cervidae DRB gene evolution mechanism other hand, for the protection of rare and endangered wild animals endemic to China black muntjac strategies that provide the basis of the functional gene. The main findings are as follows: 1. This study the bovine DRB3-specific primers (LA31 and LA32) by polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) and the clone sequencing technology, from 44 black muntjac individuals and 12 muntjac individuals were given 11 and 20 DRB exon alleles. The black muntjac lower DRB allele polymorphism with respect muntjac. 12 muntjac of 6 3-4 allele, suggesting that the use of the primers from amplified at least two DRB seats muntjac. Black muntjac individual 44 35 having two or more alleles, wherein, No. 3, No. 23, No. 34, the three samples, each having a 5 allele, suggesting that this article using the primers, amplified at least black Muntjac the 3 DRB seat. 2 sequence alignment results show that black muntjac herein, the muntjac DRB gene and bovine DRB3 has a very high homology, all serial no insertions, deletions and stop codons, in addition, of the detected amino acid mutation The sites are mainly located in the antigen-binding region to speculate that the the DRB gene may this Muntiacus two animals are the expression of the seat, according to these results. Amino acid sites of the two animals DRB genes of the antigen-binding region of non-synonymous substitutions (dN) are significantly greater than the synonymous substitutions (dS) (P lt; 0.05), implied the black muntjac history and muntjac DRB gene experienced positive selection role. M7 and M8 CODMEL program model likelihood detection (likelihood ratio test, LRT) results also support this hypothesis. Further using the empirical Bayesian method accurately detected five positively selected amino acids sites (loci 10,11,61,86 and 90) where the three sites in the PBR District of black muntjac muntjac 6 sites under positive selection (point 11,37,61,67,71 and 86), and one of the five sites in the PBR District. Therefore, the role of positive selection is one of the main mechanisms to maintain both animal DRB gene polymorphism. Based outside Mhc-DRB exon 2 sequence artiodactyl phylogenetic relationship built using the neighbor-joining (NJ) NJ tree, Muntiacus black muntjac muntjac DRB genes with other deer species DRB gene was inlaid type distribution, suggesting that cross-species evolution is another important mechanism for the maintenance of the black muntjac muntjac DRB gene polymorphism. In addition, the black muntjac allele MucrDRB8 muntjac MureDRB1 and MureDRB11 wapiti CeelDRB34 and CeelDRB46 with bovine DRB3 alleles constitute a separate clade, suggesting The Muntiacus both animals and red deer The DRB gene has a very ancient lineage.
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