【摘要】 DRA基因属Bo LA家族Ⅱ类基因,编码Ⅱ类抗原分子的α链,其第2外显子编码的抗原结合区在抗原呈递中发挥重要作用。以天祝白牦牛、大通牦牛、甘南牦牛和普通牛为研究对象,利用PCR-SSCP的方法对Bo LA-DRA基因第2外显子及第2内含子多态性进行了检测。结果表明,DRA基因第2外显子区检测到197位T>C和116位G>A突变,对应A、B和C 3种等位基因,PIC值为0.249~0.424,为中度多态。第2内含子区发现1个A>G、1个T>C突变和1个C>T突变,对应a、b、c和d 4种等位基因,PIC值为0.389~0.515,为中度及高度多态。聚类分析表明,牦牛DRA基因第2外显子区碱基序列与普通牛以及山羊的同源性最高,系统进化情况与它们亲缘关系远近一致。更多还原

【Abstract】 DRA gene,coding α chain of Ⅱ antigen molecules,belongs to the family of Bo LA Ⅱ genes. The antigen-binding region coded by exon2 of DRA gene plays an important role in antigen presentation. This study detected the genetic polymorphisms in exon2 and intron2 of Bo LA-DRA gene in Tianzhu White yak,Datong yak,Gannan yak and cattle by PCR single-strand conformational polymorphism( SSCP). The results showed that two SNPs,T > C at 197 th and G > A at 116 th,corresponding to alleles A,B and C were detected,and the polymorphism was moderate level with PIC in the range of 0. 249- 0. 424 in the exon2 of Bo LA-DRA. Four mutations,including one T > C,one C > T and one A > G,corresponding to alleles a- d were identified,and moderate or high polymorphism with PIC in the range of 0. 389- 0. 515 was observed in the intron2 of Bo LA-DRA in yak and cattle. Deduced nucleotide sequences of Bo LA-DRA*exon2 between yak,bovine and goat were the highest on homology and the phylogenetic distance consistent with their genetic relationship.更多还原