Analysis on Associations of SNPs of Leptin Gene with Growth Traits in Four Sheep Breeds

PCR-SSCP was applied to detect single nucleotide polymorphism(SNP) of exon 2 and exon 3 of the Leptin gene for 358 sheep,including Poll Dorsets(PD),Suffolks(SF),Texels(TX) and Tan sheep(Tan).The polymorphisms were demonstrated,and exon 2 and exon 3 of leptin gene were sequenced.Seven SNPs were detected,five of which were new SNPs.There is no SNP in exon2,but four SNPs were detected in parts of intron 2.They are A99G,G115A,C150T and C171T.Three SNPs occurred in exon3,all of which resulted in amino acid changes.The association between some SNPs and growth traits were analyzed.The results showed that the average values of birth weight,daily gain and withers height of Aa were significantly higher than those of AA at A99G SNP(P0.05),while the values of heart girth and rump width of Aa were very significantly higher than those of AA(P0.01).The average values of daily gain,withers height,body length,heart girth and rump width of mutantions types were significantly higher than those of wide-types at C150T SNP(P0.05).The results of A99G+C150T polymorphic site were the same to C150T SNP.