合作猪SLA-DQA基因外显子2多态性分析

Analyzing Polymorphism of SLA-DQA Gene Exon 2 in the Hezuopig

旨在研究合作猪DQA基因外显子2多态性,确定其等位基因数、核苷酸多态位点、氨基酸多态位点及各个等位基因之间的遗传关系,分析其进化意义。选用PCR-SSCP对439只合作猪SLA-DQA基因外显子2的多态性进行检测;测序群体内因变异而产生的各等位基因序列,并分析序列数据。结果显示,在合作猪SLA-DQA外显子2中发现了7个新等位基因,共18个核苷酸多态位点,10个氨基酸多态位点。合作猪SLA-DQA外显子2具有较丰富的多态性,群体内可能蕴藏着更加丰富的遗传资源;合作猪SLA-DQA外显子2基因最初可能由一个等位基因突变分化成一大类基因;合作猪SLA-DQA外显子2序列与各个猪种的SLA-DQA外显子2序列具有较高的同源性,预示着这些猪种的SLA-DQA外显子2基因最早可能来源于其分歧之前的共同祖先原始序列;新发现的7个SLA-DQA外显子2等位基因,可能由遗传关系较近的两个等位基因突变产生。

The polymorphism, allele number, nucleotide polymorphism sites, amino acid polymorphism sites, the genetic relationship and evolutionary significance of the alleles of the SLA-DQA gene exon 2 in Hezuo pigs were studied. Variation of SLA-DQA gene in the 439 Hezuopigwas investigated by amplification of exon 2 using PCR, followed by single-strand conformational polymorphism（SSCP）, DNA sequencing and sequence data analysis. Result showed that seven alleles were found in the SLA-DQA geneexon 2. Eighteen nucleotide polymorphism sites and ten amino acid polymorphism sites were identified in seven SLA-DQA gene exon 2 haplotypes. The study indicated that a high level of sequence polymorphism existed in SLA-DQA gene exon 2 of Hezuo pigs, and the population might have more genetic resources. SLA-DQA gene exon 2 in Hezuo pigs might be differentiated into two major categories alleles from one mutant alleles at first. SLA-DQA gene exon 2 in Hezuo pigs and other pig had high homology, which indicated that SLA-DQA gene exon 2 in pig might come from primordial sequences that were present in a common ancestor and persisted in the pig populations since their divergence. Seven new alleles that had near genetic relationship, may came from the two near allele by mutation.