Abstract: Prolactin receptor (PRLR) gene was studied as a candidate gene for the prolificacy in sheep. Two　pairs of primers were designed to detect single nucleotide polymorphisms of exon 10 of PRLR gene in both nonseasonal estrous breed(Hu sheep) and seasonal estrous breed(China Merino, Romilly Hills and Romilly Hills×China Merino) by PCRSSCP.The result showed that the products amplified by primer P1, P2 displayed polymorphisms. For primer P1, sequencing revealed two mutations (53A→G and 81G→A) of PRLR gene in the genotype AB and only one mutation (53A→G) was found in the genotype BB in comparison with reported sequence.And these mutations did not cause any amino acid change.For primer P2, sequencing revealed one mutation(89T→C) in genotype CC,DD,CE,EF and this mutation resulted in an amino acid change of Pro→Leu.Another mutation (146C→G) of PRLR gene in the genotype DD and this mutation resulted in an amino acid change of Ala→Gly. One mutation (132G→A) was detected in the genotype EF and CE,this mutation resulted in no amino acid change. One mutation (167G→A) was also detected in the genotype EF and led to an amino acid change Pro→Leu. The result of χ2 independence test indicated that the distribution and constitution of genotypes at P1 and P2 of the exon 10 of PRLR gene showed significant differences among 4 sheep breeds(P<0.01).

Key words: sheep; prolactin receptor gene; PCRSSCP