| With the view of studying polymorphism of DRB1 exon 3 in Tibetan sheep was analyzed, determining the number of alleles, nucleotide polymorphism sites, amino acid polymorphism sites, genetic relationship among every allele and evolutionary significance, as well as the possibility of DRB1 exon 3 as the molecular genetic markers. Using PCR-SSCP method, we detected 500 Tibetan sheep DRB1 gene exon 3 alleles at the first time, and cloning and sequencing every allele which comes from variation in population, then analyzing the haplotype sequence data of allele. This study aimed to bioinformatics of DRB1 in ovine MHCⅡarea. The physicochemical characteristics, structures and functions of ovine MHC-DRB1 were predicted and analyzed with software tools and database. Meanwhile, the phylogenetic tree of DRB1 and related proteins was constructed.Total of 8 alleles were identified, in which 7 alleles has not been reported before. And there were 15 SNPs sites in DRB1 gene haplotype. The phylogenetic tree results showed that the 8 haplotypes of Tibetan sheep DRB1 exon 3 could divide into two clusters. It is showed that Tibetan sheep DRB1 gene is differentiated into two major categories alleles from two mutant alleles at first. The result of OLA-DRB1 is unstable hydrophilic proteins. It has very obvious signal peptide.The secondary structure was primarily composed of random coil and sheet. It mainly exerts the biological effects in the cytoplasm. Sequence analysis indicated that this gene suggested it maybe involved in immune response, receptor, stress response and signal transducer roles, it may play important roles in immune response and stress response, The results suggested that MHC-DRB1 might play a key role in immunity and disease resistance in ovine.The DRB1 and related proteins of Ovine, Capra hircus, Rupicapra rupicapra, Hemitragus jemLahicus, Bos Taurus on such species are close together in the phylogenetic tree, they are highly homology. |
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