Study On Genetic Polymorphism Of HSL Gene Exon Ⅰ And Effect Of MC4R Gene On Economic Traits In Pigs

Adopting Polymerase Chain Reaction-Restrain Fragment Length Polymorphism (PCR-RFLP),the genetic variation of Hormone-sensitive lipase(HSL) gene exon I and Melanocortin-4 Receptor (MC4R) gene were detected in 659 pigs including 7 population (Duroc, Landrace, Yorkshire, LY, Ningxiang, Shaziling, Daweizhi),then genotype frequencies and gene frequencies were counted according to the PCR-RFLPs and the distribution of genotype frequencies in the population were analyzed by Chi Square Test. The effects of MC4R gene on Growth traits , Carcass traits and Meat quality traits were estimated .The main results were showed as follows:1.Genetic polymorphism of HSL gene exon I:The distribution of genotype is significantly different among 5 breeds. There exist only GG genotype in lean-type Large White and Landrace pigs. Duroc and native breeds (ningxiang and daweizhi) have three genotypes (AA AG GG), allele A frequencies of three breeds is 0.3979,0.7272,0.7295 respectively. While there are higher frequencies of allele G in the foreign breeds, there are higher frequencies of allele A in the native breeds.2.Genetic polymorphism and effect of MC4R gene(1) The distribution of genotype is significantly different among 6 breeds. In four foreign breeds, there are three genotypes (AA AB BB ) , allele A frequencies of four breeds is 0.6301,0.2600,0.5141,0.3889 respectively .There exist only BB genotype in fat-type Shaziling and Daweizhi pigs.(2) There are considerable model effects on 100kg days, Loving Mean BFT, Loving modified BFT, Growth Index. The allele A has effects of reducing Loving BFT and enhancing Growth Index. But the effects are different in different breeds.(3) Among all carcass traits and meat quality traits, there are considerable model effects. In there genotypes, Real mean BFT and Fat Percentage of the pigs with genotype AA are lower than that of the pigs with genotype BB, while the Meat percentage of the pigs with genotype AA is higher than that of the pigs with genotype BB. Genotype AA performs negative effects on Real mean BFT, Fat Percentage and positive effects on Meat Percentage .As Marble Score and Meat Color Score are concerned, the pigs with genotype AB are better than the others.The purpose of this study is to provide theory basis for improving the Growth traits, Carcass traits and Meat quality traits...