北京黑猪FSHb 亚基基因的多态性与繁殖性状的关联分析

本研究以北京黑猪为研究对象, 以FSHb 亚基基因为产仔性状的候选基因, 分别采用PCR产物直接电泳和PCR-RFLP方法来检测FSHβ亚基基因2个位点的多态性。结合测序发现: FSHb-1位点上, 北京黑猪BB型的134与135 bp (D00621序列的6 473与6 474 bp) 之间插入273 bp的片段而产生多态, 序列分析表明该插入片段为一典型的逆转座子, 在插入片段中还发现了一个RNA 聚合酶Ⅲ内部启动子; FSHb-2位点上, 由于扩增片段173 bp处存在C→T的突变, 使得HaeⅢ酶切位点消失而产生多态; 2个位点的A、B等位基因在北京黑猪群体中都有分布, 且处于低度多态。χ2适合性检验结果表明, 该群体在这2个位点的突变都达到Hardy-Weinberg平衡状态 (P>0.05)。用SAS 8.2 软件最小二乘法拟合线性模型, 将基因座不同基因型与繁殖性状总产仔数 (TNB)、产活仔数 (NBA) 和出生重 (WB) 进行了关联分析, 结果表明: 就初产母猪而言, FSHb-1位点上, AA型比AB和BB型个体的TNB分别多0.96头和1.85头 (P＜0.05), AA和AB型比BB型个体的NBA分别多0.95头和1.69头(P＜0.05)。FSHb-2位点上, AA型比AB型和BB型个体的TNB分别多1.57头和2.15头 (P＜0.05); AA和AB型比BB型个体的NBA分别多1.00头和0.94头 (P＜0.05); 就经产母猪而言, FSHb-2位点上, AA型个体的WB比BB型的WB重0.25 kg (P＜0.05)。全部群体的FSHb-1位点的A等位基因和初产母猪FSHb-2位点的A等位基因对TNB、NBA和WB表现为正效应。

Genetic polymorphism of FSH b subunit gene and correlation with reproductive traits in Beijing black pig

FSH beta subunit gene was regarded as a candidate gene for reproductive traits of Beijing Black Pig in this study. The polymorphism of two loci FSHbeta-1 and FSHbeta-2 was detected by electrophoretic method and PCR-RFLP with restriction endonuclease Hae III. Sequencing results showed that a 273 bp sequence, which was a retrotransponsons including a RNA Polymerase III inter promoter, was inserted between the 134th and 135th nucleotide of the PCR product in FSHbeta-1, and the mutation (C-->T) was revealed at the 173th nucleotide of the PCR product in FSHbeta-2. Both alleles (A and B) of both loci were found in the population that showed low polymorphism. Chi-square test indicated that the two polymorphism sites fitted Hardy-Weinberg equilibrium (P>0.05). The effects of polymorphism of FSH b subunit gene on total born number (TNB), number born alive (NBA), and birth weight (WB) were analyzed. For FSHbeta-1 locus, pigs of the first parity with genotype AA had 0.96 and 1.85 TNB more than those with genotypes AB and BB. The pigs of the first parity with genotypes AA and AB had 0.95 and 1.69 NBA more than those with genotype BB, respectively. For FSHbeta-2 locus, pigs of the first parity with genotype AA had1.57 and 2.15 TNB more than those with genotypes AB and BB. The pigs of the first parity with genotypes AA and AB had 1.00 and 0.94 NBA more than those with genotype BB, respectively. The pigs of multiparous with genotype AA had 0.25 kg of WB more than those with genotype BB. The results of combined genotype effects indicated that A allele of FSHbeta-1 locus in all the population and FSHbeta-2 locus in pigs of the first parity had the positive effective on TNB, NBA, and WB.