多胎基因FecB对德×寒×细三元杂交羊产羔性能的影响

为了研究FecB基因在德×寒×细三元杂交羊群体中的多态性分布及与产羔性能指标的相关性,该试验将以德国肉用美利奴羊（以下简称德肉美）为父本,以小尾寒羊公羊与东北细毛羊母羊级进杂交生产的F₂代羊为母本（以下简称寒×细F₂母羊）,生产的三元杂交后代羊（以下简称德×寒×细三元杂交羊）作为研究对象,采用KASP方法分析FecB基因型并计算基因频率和基因型频率,分析FecB基因频率与德×寒×细三元杂交羊群体产羔性能的相关性。结果发现,德肉美并不含有FecB基因,德×寒×细三元杂交羊B等位基因频率增加明显且处于Hardy-weinberg不平衡状态,提示人工选择对杂交羊群体FecB基因富集影响较大。对寒×细F₂代母羊和德×寒×细三元杂交羊群体不同基因型个体产羔数进行秩和检验分析发现,P值均小于0.01,平均产羔率均表现为++基因型小于B+和BB基因型（P<0.05）,说明B等位基因对德×寒×细三元杂交羊群体产羔性能的提升发挥重要作用。该试验为利用FecB基因提升德×寒×细三元杂交羊群体产羔性能提供参考。

Effect of FecB Gene on Lambing Performance of Germany Mutton Merino Sheep×Small-tailed Han Sheep×Fine-wool Sheep Ternary Hybrid Sheep

The objectives of this study were to verify the pleomorphic distribution of FecB gene in the ternary hybrid sheep of Germany Mutton Merino sheep×small-tailed Han sheep×fine-wool sheep, and to assess its correlation with lambing performance of the ternary hybrid sheep. German Mutton Merino sheep and the F₂ hybrid sheep produced with small-tailed Han rams and northeast fine-wool ewes were used as the male parent and female parent, respectively, to produce the ternary hybrid sheep. The KASP method was used to analyze the genotype of FecB, and its gene frequency and genotype frequency were calculated. Furthermore, the correlation of gene frequency of FecB with the lambing performance of the ternary hybrid sheep flock was assessed. FecB gene was absent in German Mutton Merino sheep. The B allele frequency of the ternary hybrid sheep was increased significantly and was in a Hardy-weinberg imbalance state, indicating that the artificial selection had a great impact on FecB gene enrichment in hybrid sheep. The rank-sum test analysis on litter size of the individuals of F₂ hybrid ewes and ternary hybrid sheep with different genotypes demonstrated the P value were all less than 0.01, and for the two sheep flocks, the average lambing rate of the individuals with ++ genotype was both lower than those with B+ and BB genotypes （P<0.05）. It is indicated that the B allele play an important role in improving lambing performance of the ternary hybrid sheep. This study provides a reference for ameliorating the lambing performance of the ternary hybrid sheep using FecB gene.