小尾寒羊MHC-DRB3基因外显子2的多态性分析

Polymorphisms of Exon2 of MHC-DRB3 Gene in Little-Tailed Han Sheep

采用PCR-RFLP方法对小尾寒羊MHC-DRB 3基因第二外显子285 bp的扩增产物进行多态性分析,结果共检测到内切酶P stⅠ的3种基因型,由2个等位基因控制,通过酶切图谱分析结果表明:小尾寒羊的MHC-DRB 3基因第二外显子的第241位的碱基表现出多态性,等位基因B的基因频率为0.81879。x2适合性检验结果表明:小尾寒的MHC-DRB 3基因的第2外显子的P stⅠ酶切位点达到了H ardy-W e inberg平衡状态。

MHC （Major Histocompatibility Complex） is a chromonsomal region consisting of a group of closely linked loci which are highly polymorphic, which plays a central role in the immune system of animals and is almost found in all vertebrates. Its expressional product is MHC antigen of which main function is antigen presentation. In this study, the exon2 of MHC-DRB3 gene was amplified by PCR and a uniform fragment of 285 bp was obtained in Little-Tailed Han Sheep. The 285 bp PCR product was digested with restriction endomuclease Taq I .Pst I and genetics polymorghism was investigated by PCR-RFLP. Two alleles were found： A（285 bp）, B（270/15 bp）. There are three genotypes in the tested population. Statistical results indicated that the frequency of B allele is 0. 6948. The result of x^2test shows that genotypes of MHC-DRB3 gene in Little-Tailed Han Sheep fit with Hardy-Weinberg equilibrium.