摘要:
为寻找与山羊(Capra hircus)产羔数密切相关的分子标记,加快山羊育种进程,研究转化生长因子β1基因(TGF-β1)遗传多态性与山羊产羔数的相关性,根据牛的TGF-β1基因序列设计3对引物,采用PCR-SSCP.和DNA测序技术检测山羊TGF-β1基因外显子2和内含子3的多态性,同时用最小二乘法研究了其多态性与产羔数的关系.结果表明,在波尔山羊和陕南白山羊中,仅第二外显子148 bp位点碱基发生A→G的突变,导致苏氨酸(Thr)变为丙氨酸(Ala);多态位点均以A为优势等位基因,基因频率分别为0.530和0.648.在波尔山羊的1~3胎产羔数中,AB型个体的产羔数显著高于BB和AA型个体(P<0.05);在第四胎产羔数和平均产羔数中,AB型个体的产羔数显著高于AA(P<0.05),显著高于BB(P<0.05); BB型个体的平均产羔数显著高于AA型(P<0.05).在陕南白山羊中,AB型个体的2~4胎产羔数和平均产羔数显著高于AA和BB型个体(P<0.05);在第一胎中,AB型个体显著高于AA型个体(P<0.05).研究结果表明TGF-β1基因多态位点与产羔数显著相关,可以用于山羊分子遗传育种的候选基因.%In order to find the molecular marker used in marker-assisted selection (MAS) to accelerate goat [Capra hircus) breeding progress, the goat transforming growth factor-pi gene(TGF-β1) was selected to study the association between its polymorphism and litter size. According to the sequence of bovine TGF-β1 gene, three pairs of primers were designed to detect SNPs of intron 3 and exon 2 of TGF-(3 gene in two goat breeds by PCR-SSCP and DNA sequencing. The least square mean and genetic variance of different genotypes at polymorphic loci were analyzed. The results showed that the PCR products of primer 1 (P1) had polymorphism. Three genotypes (AB, BB, and AA), and one single nucleotide mutation (A-?G) was detected in two goat breeds, and this mutation resulted in an amino acid change: Thr→Ala. Allele A was the dominant allele. The frequencies of allele A were 0.530 and 0.648 in two goat breeds, respectively. In Boer goat, AB genotype had significantly higher (P<0.05) litter size than that of BB and AA genotypes from the first to third parity. AB genotype was very significantly higher (P<0.01) than that of AA genotype, and significantly higher (P<0.05) than that of BB genotype, and BB genotype was significantly higher (P<0.05) than that of AA genotype in the fourth parity and average litter size. In Shaannaa goat, AB genotype had significantly higher (P<0.05) litter size than that of AA and BB genotypes in the second, third, fourth and average parity, and AB and BB genotypes had significantly higher (P<0.05) litter size than that of AA genotype in the first parity. The TGF-β1 gene had significant effects on litter size in two goat breeds. Therefore, these results suggest that the TGF-β1 gene is a strong candidate gene that affects litter size in goats.