Polymorphism Analysis Of Several Functional Genes Which Relates To Sheep's Reproductive Traits

High prolificacy-related BMPR-IB,BMP15,GDF9,ER,MTNR1A and PRLR genes were selected as candidate genes.These genes'genetic polymorphisms were analyzed by PCR-RFLP and PCR-SSCP method in Hu,China Merino,Romilly Hills amd Romilly Hills×China Merino Sheep.1.The polymorphism of BMPR-IB gene was analyzed by PCR-RFLP method.The result showed that FecB mutant of BMPR-IB gene was only found in Hu sheep, the frequence of B allelomorphic gene was up to 0.784.It was medium polymorphism.The result ofχ~2 fitness test indicated that it was in Hardy-Weinberg equilibrium(P>0.05). The result ofχ~2 independence test indicated that the distribution and constitution of genetypes at this site showed significant differences among this four sheep breeds(P<0.01).2.The polymorphisms of BMP15 and GDF9 genes were analyzed by PCR-RFLP method. No FecG~H homozygous mutant of GDF9 and FecX~I,FecX~H,FecX~G(B2),FecX~B(B4)mutants of BMP15 were found in Romilly Hills and China Merino.In Hu and Romilly Hills×China Merino,No FecGH homozygous mutant of GDF9 and FecX~I,FecX~H,FecX~G(B2)mutants of BMP15 were detected,and FecX~B(B4) heterozygous mutant of BMP15 was found,its genetype were all +B.3.The polymorphism of ER gene's 5'non-translation region was analyzed by PCR-SSCP method. The result indicated that there was no mutation in this four breeds.4.Genetic polymorphism of the exon 2 of MTNR1A gene was detected by PCR-RFLP.The result showed that MnlⅠand RsaⅠpolymorphic sites were detected at base position 605 and 604.The mutation rate were high At MnlⅠsite in Hu and China Merino,The frequency was up to 0.784 and 0.86.At MnlⅠand RsaⅠsites in four sheep breeds, the result ofχ~2 fitness test indicated that they were all in Hardy-Weinberg equilibrium(P>0.05).The result ofχ~2 independence test indicated that the distribution and constitution of genetypes at MnlⅠand RsaⅠsites showed significant differences among this four sheep breeds(P<0.01).5.By PCR-SSCP, the polymorphisms of the specific fragments which were amplified by five primers in 3'non-translation region and the exon 10 of PRLR gene were examined.The fragments which were amplified by PRLR2 and PRLR3 showed polymorphic.For PRLR2,sequencing revealed two mutations (53A→G and 81G→A) in the genotype AB and only one mutation (53A→G) was found in the genotype BB in comparison to reported sequence.And these mutations did not cause any amino acid change.For PRLR3, sequencing revealed one mutation (89T→C) in genotype CC,DD,CE ,EF and this mutation resulted in an amino acid change of Pro→Leu.The mutation (146C→G) was found in the genotype DD and resulted in an amino acid change of Ala→Gly.The mutation (132G→A) were detected in the genotype EF and CE(single homologous chromosome),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 ofχ~2 independence test indicated that the distribution and constitution of genetypes at PRLR2 and PRLR3 of the exon 10 of PRLR gene showed significant differences among this four sheep breeds(P<0.01).