Abstract: [Objective and Method]The polymorphism of bone morphogenetic protein receptor type IB gene (BMPR-IB gene) of 204 sheep of three breeds or strains ,which included Small Tail Han sheep,F_1 generation from German Merino(♂)×Small Tail Han sheep(♀) cross generation （DF1）, German Merino ,was analyzed by PCR-sscp. The relationship between genotype and litter size was also identified.[Result and Conclusion]The results showed that the frequency of B allele in Small-Tail Han sheep, German Merino and DF1 was 0.660,0.532 and 0.600，there was no significant difference of distribution of gene frequency and genotype frequency in 3 groups.The litter size of BB,B+ and ++ was 2.86,2.27 and 2.08，BB were both significantly higher than B+ and ++ (P＜0.05),and B+ were significantly higher than ++ type.

摘要： [目的]分析小尾寒羊、德国美利奴、德国美利奴(♂)和小尾寒羊(♀)杂交一代(简称DF1)共204 只个体的单核苷酸多态性及其与产羔数间的关系.[方法]以绵羊BMPR-IB 基因作为候选基因,采用PCR-sscp 检测方法.[结果]B等位基因在小尾寒羊、德国美利奴、德寒杂交一代中的频率分别为0.660、0.532和0.600,基因频率及基因型频率在3个群体间的分布差异不显著(P>0.05).BB、B+、++型的产羔数分别为2.86、2.27和2.08,BB 型显著高于B+ 和++ 型(P>0.05),B+ 型显著高于++ 型(P>0.05).[结论]在以小尾寒羊为母本的杂交育种过程中,B等位基因是有效的辅助标记基因.