摘要
以绵羊 BMPR-IB 基因为候选基因,应用 PCR-RFLP 方法通过分析湖羊、夏洛来、陶赛特、萨福克、罗米丽、中国美利奴羊、中国美利奴肉用多胎品系以及陶赛特×中国美利奴羊和萨福克×中国美利奴羊杂交后代共 615 只个体的 FecB基因多态性,以及 BMPR-IB 基因多态性对产羔数、体尺和体重的影响。结果表明,BMPR-IB 基因在不同品种(系)绵羊中共有 3 种基因型(BB、B+和++),但基因型频率分布在各品种(系)间差异极显著(P<0.01)。在湖羊中仅有 BB 基因型;在中国美利奴肉用多胎品系中 BB、B+和++基因型频率分别为 51%、30%和 19%;而其他品种(系)羊中则仅有++基因型。对中国美利奴羊肉用多胎品系研究,发现 BB 和 B+基因型群体平均产羔数分别为 2.8 和 2.3,显著高于++基因型群体(1.2,P<0.01)。在 90 日龄时,BB 和 B+基因型群体的体重分别为 18.6±3.70 kg 和 18.0±3.31 kg,显著高于++基因型群体(15.6±2.22 kg,P<0.05);此外,90 日龄时,BB 和 B+基因型群体比++基因型群体胸围、胸宽较大(P<0.05);但这些差异在120 日龄时消失。另外,我们还发现不同地区群体的第一胎产羔数存在明显差别。这些结果表明,BMPR-IB 基因为影响绵羊产羔数的主效基因,并首次证明该基因对后代羔羊出生后生长发育具有加性效应。
Nine sheep breeds or strains, including 615 individuals were screened with forced PCR RFLP method for the FecB gene to study the polymorphism and its effects on litter size, body weight and body size. Results showed that the polymorphism frequencies of FecB gene were significantly imbalanced in these breeds or strains. The Hu sheep were all homozygous carriers of FecB gene（BB）. In the Chinese Merino prolific meat strain, the genotype frequencies of BB, B＋ and ＋＋ were 51%, 30% and 19%, respectively, whereas all the other flocks had only the wild-type （＋＋） genotype. Results within the Chinese Merino prolific meat strain showed that the mean litter size of ewes with genotype BB and B＋ were 2.8 （±0.74） and 2.3 （±0.63） （P〈0.05）, whereas ＋＋ genotype ewes had a litter size of only 1.2 （±0.68） （P〈0.01）. At day 90 after birth, the body weights of BB/B＋ genotype lambs were higher than that of ＋＋ genotype lambs （18.6±3.70 kg, 18.0±3.71 kg vs 15.6±2.22 kg, P〈0.05）. In addition, the heart girth and chest width of BB/B＋ genotype lambs were significantly longer than those of the ＋＋ lambs （P〈0.05）. No significant differences were observed in either body weight or body size at day 120. Litter size at first lambing from Hu at Natural Source Conservative Region was found to be significantly higher than that from the other two regions sampled （P〈0.05）. In addition to the additive effect on litter size, these findings showed for the first time that the FecB gene had a positive effect on early postnatal body growth.
基金
This work was supported by the Natural Science Foundation of Zhejiang Province of China (No.Y 305107) and Shanghai Key Pro-ject of Science and Technology Service for Agriculture(No.2002, 1-3-6)
