八眉猪SLA-DRA基因第2外显子多态性分析

Polymorphism of SLA-DRA exon 2 in Bamei pigs

为了解八眉猪SLA-DRA基因第2外显子的多态性,采用PCR-SSCP和克隆测序的方法对八眉猪SLADRA基因第2外显子进行分型,并对不同等位基因进行核苷酸与氨基酸序列分析。结果显示,222头八眉猪中共检出2种等位基因(A和B)和3种基因型(AA,BB和AB),其中A等位基因和AA基因型的频率最高,为优势基因和优势基因型。对不同SSCP带型的对应片段进行测序分析,发现该基因仅有一个核苷酸突变位点(c.3093 A→C),为错义突变,使甲硫氨酸(Met)变为亮氨酸(Leu),并且该氨基酸位于抗原结合位点上。群体遗传学分析发现,八眉猪遗传杂合度(He)为0.351 4,多态信息含量(PIC)为0.308 8,且经χ2适合性检验,八眉猪在此位点上没有偏离Hardy-Weinberg平衡状态(P>0.05)。八眉猪SLA-DRA基因第2外显子的多态性较低。

In order to study polymorphism of SLA-DRA exon 2 in Bamei pigs, genetic variation of SLA-DRA exon 2 in Bamei pigs was identified by polymerase chain reaction-single strand conformation polymorphism and cloning, both the nucleotide and the amino acid sequences of the different alleles were analyzed. The results showed that two alleles （ A, B） and three genotypes （ AA, BB, AB） of SLA-DRA exon 2 were detected from 222 Bamei pigs, the frequen-cies of the A allele and AA genotype were the highest, and A and AA were dominant. The results of sequencing showed that only one mutational nucleotide site （ c. 3093 A→C） and one amino acid site （ p. Met→Leu） were iden-tified. Genetic heterozygosity was 0. 3514, and polymorphic information content （PIC） was 0. 3088, which meaned SLA-DRA exon 2 in Bamei pigs was moderately polymorphic （0. 25 〈PIC 〈0. 5）. The chi-square analysis suggested that the allele and genotype frequencies were not deviated from Hardy-Weinberg equilibrium （P 〉 0. 05）. The find-ing showed that polymorphism of SLA-DRA exon 2 in Bamei pigs was low.