Abstract: Prolactin receptor (PRLR) gene was studied as a candidate gene for the milk performance of in Xinong Saanen dairy goat. Four pairs of primers were designed to detect single nucleotide polymorphisms of exon 10 of PRLR gene by PCR-SSCP. The results showed that only the products amplified by primer P1 didn’t display polymorphisms. For primer P2,two genotypes (AA and AB) were detected in Saanen dairy goat.Sequencing revealed two mutations of PRLR gene in the genotype AA in comparison to the genotype AB, The mutation C27T did not cause any amino acid change,The deletion of 189th result in two amino acid changes of His→Tyr and Thr.The difference of the least squares means (LSM) for milk yield between AA and AB was significant (P<0.05) in Saanen dairy goat, the third lactation milk yield of individuals with genotype AA was higher than that with genotype AB(P<0.05).For primer P3, three genotypes(CC,CD,DD) was detected in Saanen dairy goat.Sequencing revealed two mutations(C103A and T106C) of PRLR gene in the genotype CC in comparison to the genotype DD. The former mutation resulted in an amino acid change of Lys→Thr,and the later mutation resulted in an anino acid change Thr→Ile.The difference of LSM for milk yield among CC,CD and DD was non-significant(P>0.05).For primer P4,two genotypes(EE and EF) were detected in Saanen dairy goat. Sequencing revealed one mutation(A114G) of PRLR gene in the EE in comparison to the genotype EF,and this mutation resulted in an amino acid change of Met→Val. The difference of the LSM for milk yield between EE and EF was significant (P<0.05) in Saanen dairy goat,The milk yield of individuals with genotype EE was higher than that with genotype EF in third,fourth lactation milk yield and average milk yield (P<0.05).Based on these results,it was indicated that PRLR gene had significant positive effects on milk performance of dairy goats.Additionally, The exon 10 of PRLR gene can be regarded as effective molecular markers on MAS program for milk performance of dairy goat.

Key words: Xinong Saanen dairy goat, PCR-SSCP, PRLR gene, milk performance