Polymorphism Analysis On Leptin Gene And Association With Litter Size Performance In Four Anhui Local Pig Breeds

Leptin gene, which contains three exons and two introns, takes part in the function of regulating body weight, adjusting reproduction, keeping the energy balance and so on. We took different breeds including Anqingliubai Pig, Wannan Black Pig, Wannanhua Pig and Dingyuan Black Pig as research objects, which had perfect germplasm characteristics to study the Leptin gene's SNPs(Single Nucleotide Polymorphisms,SNPs) and relation with reproduction performance.In this study, we analyzed the polymorphism of sows'Leptin gene by PCR-SSCP. In order to find the correlation between Leptin gene and reproduction performance, provide the molecular genetic markers for porcine breeding and lay the foundation for Marker-assisted selection, we designed three pairs of primers according to the Leptin sequence obtained from GenBank database to amplify the second and third exons and analyze them.The results showed:1,Among the three pairs of primers, there existed SNPs in primer2 and primer3. We have found that there was no mutation site in the second exon, but there were two mutation sites(T3469C and G3717T) in the third exon.2,The genetic analysis indicated that there were three genotypes in primer2 (AA,AB,BB)and three genotypes in primer3(CC,CD,DD) in four Anhui breeds. They belonged to two mutation sites and were silent mutation.In T3469C site, the genotype frequencies of AA,AB,BB were 0.3236,0.5882,0.0882 in Anqingliubai Pig, respectively; the genotype frequencies were 0.3530,0.5686,0.0784 in Wannan Black Pig, respectively; the genotype frequencies were 0.2182,0.6182,0.1636 in Wannanhua Pig, respectively; the genotype frequencies were 0.3699,0.4795,0.1506 in Dingyuan Black Pig, respectively.In G3717T site, the genotype frequencies of CC,CD,DD were 0.4706,0.4706,0.0588 in Anqingliubai Pig, respectively; the genotype frequencies were 0.3333,0.4902,0.1765 in Wannan Black Pig, respectively; the genotype frequencies were 0.4182,0.4909,0.0909 in Wannanhua Pig, respectively; the genotype frequencies were 0.4521,0.3699,0.1780 in Dingyuan Black Pig, respectively.The test of Hardy-Weinberg equilibrium showed that genotypic frequencies of Leptin gene were in equilibrium. There was abundant polymorphism of Leptin gene in 4 Anhui breeds.3,In this study, litter size performance included LSP, LS1 and LSa. After analyzing the differences among the genotypes of both sites by using GLM of SAS, we know that there were significant differences in both sites of Anqingliubai. And in T3469C site, the Wannan Black Pig had significant difference with LSP, while in G3717T sites, the Wannanhua Pig had a high linkage with LSP. The Dingyuan Black Pig had no significant effect in both sites.The results show that the Leptin gene may have a potential effect on litter size of porcine. We can apply this conclusion in MAS of porcine breeding. Because of lacking the samples, it may take an effect of results, so we would increase the numbers of pigs.