滇南小耳猪与巴马小型猪SLA-DQA基因多态分析

Studies on the Polymorphism of SLA-DQA Gene between Diannan Small-ear Pig and Bama Pig

对滇南小耳猪和巴马小型猪的SLA-DQA基因的部分内含子1、完整的外显子2和部分内含子2共341bp片段进行了PCR-RFLP酶切分型,结果表明:2品种经EcoRⅠ酶切后BB基因型频率(0.468 8)高于AB型(0.375 0),AA型最低(0.156 3),B为优势基因(0.656 3),A为劣势基因(0.343 7)。经AluⅠ酶切后,滇南小耳猪MM基因型频率(0.500 0)高于MN型(0.321 4)和NN型(0.178 6);而巴马猪则以MN基因型频率(0.485 3)高于MM型(0.338 2)和NN型(0.176 5);2个品种中M等位基因(0.604 2)频率高于N等位基因(0.395 8)。经分析表明,2猪种在两酶切位点上各分型已达Hardy-Weinberg平衡。巴马小型猪和滇南小耳猪中分别存在9种和7种PCR-RFLP组合基因型,其中BBMN为优势组合基因型,AAMN为劣势组合基因型;AAMM组合基因型在2品种间差异显著(P<0.05)。遗传多态参数分析表明:SLA-DQA基因外显子2的两酶切位点在2猪种间均表现为中度多态,AluⅠ的基因多样性略高于EcoRⅠ,巴马小型猪杂合性略高于滇南小耳猪,2品种间遗传距离为0.000 4。

The partial intron 1, complete exon 2 and partial intron 2 of SLA-DQA gene was amplified and a uniform fragment of 341bp was obtained in Diannan small-ear pigs （DN） and Bama miniature pigs （BM）. After PCR products were purified and digested by EcoR Ⅰ and Alu Ⅰ, the results showed that the genotype frequency of BB （0. 468 8） at EcoR I-RFLP site was higher than that of AB （0.375 0） and AA （0.156 3）, respectively. By comparing with the allelic frequency, the predominant allele was B（0.656 3） ,while the inferior allele was A （0.343 7）. To the Alu Ⅰ-RFLP site, the genotype frequency of MM （0.500 0） was higher than that of MN（0. 321 4） and NN（0.178 6） in DN, respectively. While the genotype frequency of MN （0.485 3） was higher than that of MM （0.338 2） and NN （0.176 5） in BM, respectively. The allelic frequency of M （0.604 2） was higher than that of N（0.395 8） in two breeds. The results of χ^2 analysis showed that genotypes of the SLA DQA gene in two breeds fit Hardy-Weinberg equilibrium. There are nine and seven composite genotype of SLA-DQA gene in BM and DN, respectively. Among them, the most favorable was BBMN, while the inferior was AAMN, the genotype frequency of AAMM were found to be significantly different between two pig breeds（P〈0.05）. The resultsof genetic parameters showed that there were moderate polymorphic in exon 2 of SLA-DQA gene, the polymorphism information content （PIC） at Alu I site was higher than that at EcoR I site, the slightly higher heterozygote existed in BM than that in DN, the Nei＇s unbiased genetic distance is 0.000 4 between two breeds.