中文摘要：

通过对甘孜藏猪、合作猪、巴马猪以及五指山猪4个群体的SLA—DMA基因第2和第3外显子的PCR-SS-CP和序列多态分析表明：SLA—DMA基因的第2外显子没有多态，但第3外显子有2个等位基因的变异。通过优化低离子强度单链构象多态分型条件（LIS-PCR—SSCP）、克隆测序、菌落PCR、菌落不对称PCR及单链DNA二级结构计算机预测等技术，对第3外显子PCR—SSCP复杂带型进行了准确的判定，J等位基因的带型与单链DNA二级结构计算机预测结果之间存在很高的一致性。4群体中SLA—DMA基因的第3外显子共有JJ／JK／KK3种基因型，均达到了Hardy-Weinberg平衡。其中K等位基因频率高于J等位基因频率。杂合度和多态信息含量的高低依次为：巴马猪、五指山猪、合作猪、甘孜藏猪。除甘孜藏猪多态信息含量为低度多态外，其余群体均为中度多态。

英文摘要：

The polymorphisms of exon 2 and exon 3 in the SLA-DMA gene were studied based on the PCR-SSCP patterns and the sequences in Ganzi Tibetan pigs （T）, Hezuo pigs （HZ）, Bama pigs（BM） and Wuzhishan pigs（WZS）, no allelic variation was recognized in the second exon, but two allelic variations were recognized in the third exon in four different miniature breeds of swine. By optimizing a low ionic strength solution （LIS） PCR-SSCP, cloning sequencing, bacterical colony PCR, asymmetric PCR and structure prediction of DNA single-strand, the complicated patterns about allele K and J based on PCR-SSCP in the exon 3 were confirmed. There was highly identity comparing the pattern of allele J with the predicted second structure of DNA singlestrand. The frequencies of three kinds of genotypes JJ, JK, KK in the third exon of SLA-DMA gene were fit with Hardy-Weinberg equilibrium in four populations. The frequency of allele K was higher than that of allele J. Values of the heterozygosity and the polymorphism information contents in the exon 3 of SLA-DMA gene were showed low polymorphism in T, but moderate polymorphisms in BM, WZS,and HZ.