Abstract：The Leptin gene, which is previously known as obese gene is the major candidate gene for production traits research of cattle and sheep. To analyze the association of Leptin gene polymorphisms and sheep (Ovis aries)production in Gansu Alpine Merino, the genetic polymorphisms of part of exon 3 of Leptin gene in Gansu Alpine Merino were detected by PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) and effects of different PCR-SSCP genotypes and alleles of Leptin gene with related growth traits were analyzed. The results showed that 2 SNPs (G271A and G433A) corresponding to 4 alleles (A, B, C and D) and 4 genotypes (AA, AB, AC and AD) were detected in the exon 3 of Leptin gene in Gansu Alpine Merino. Two alleles (B and D) and 1 SNPs (G433A) were firstly reported. The alleles A with the frequency of 0.6586 and genotype AC with the frequency of 0.4095, respectively, were the highest. The association analysis results of polymorphism and growth rate indicated that genotype AC influenced significantly the individual weight of 1, 2 and 4 months samples (P<0.05) than that of other genotypes. The allele C associated significantly weight and average daily weight gain of 1, 2 and 4 months samples(P<0.05). The samples with the allele A or the genotype AC had better weight than samples with other alleles and genotypes. The results of this study suggest that the exon 3 of Leptin gene is polymorphic in Gansu Alpine Merino, and the allele C and genotype AC can be used as effective genetic markers to improve the group production performance of Gansu Alpine Merino. The findings also provide basic data for Leptin gene genetic characteristics research of sheep.
