| As the most important meat product, people pay more and more attention on the meat quality and food safty of pork. Our country is the world’s biggest producer and consumers of pork, with the share of about half of the total production and consumption of the whole world, we can’t live without pork. The meat quality of pork is a complicated character, which is affected by a variety of meat genes because of the change of nucleotide sequence. Myf5gene is one of myogenic regulatory factor family, which control the early differentiation of muscles and is one of the candidate genes that affect meat quality. The early research about polymorphism of Myf5gene is researching the correlation between SNPs which distribute in part of the Myf5gene fragment and meat quality, but rarely amplifying the overall length of Myf5gene, especially no systematic analysis of the local pig breed of Shanzhu.In this study we tested some meat quality of different bloodlines of Shanzhu populations and used PCR-SSCP to amplify the whole coding sequence of Myf5gene to find the whole mutation sites in the coding sequence, and analysis the polymorphism of Myf5gene exons. SPSS statistics16.0was used to analyze the association of Myf5allelic variants and haplotypes with some production traits. what’s more, we used fluorogenic quantitative PCR to detect the expression quantity of Myf5gene in longissimus dorsi and analysis the difference of expression quantity in different genotype and haplotype individuals, and then study the interaction between single mutation site or multiple mutation sites、expression quantity of Myf5gene and meat quality.The result of Myf5gene polymorphism research show that different bloodlines of Shanzhu populations have significant difference on shear force and protein content (p<0.05), but different genders of pigs have no significant difference on that (p>0.05); We find a total of two SNPs on exon1.The first SNP is A'C in355bp causing Met'Leu substitution in the77th amino acid, which form two genotyoes(AA and AC); The second SNP is G'C in438bp causing a synonymous mutation (Leu'Leu) in the104th amino acid, which form two genotypes (GG and GC), both of the mutations were not found homozygous mutant-type alleles; the distribution of genotype and haplotype are significant difference in different lines (p<0.05). A/C allele significantly influence protein content (p<0.05) but G/C allele don’t (p>0.05); A/C or G/C allele alone both have no significant effect on the shear force(p>0.05), however, M-S type(both sites are mutated) have significant influence on shear force(p<0.05), which mean interaction of the two mutations will be generate new genetic effects. The distribution of three haplotypes A-G(both sites are not mutated),A-S(the second site is mutated) and M-S(both sites are mutated) have significant difference in different bloodlines of Shanzhu populations (p<0.05); M-S type not only significantly influence protein content but also shear force (p<0.05).The result of fluorogenic quantitative PCR show that expression quantity of Myf5gene have significant difference in different lines (p<0.05),but don’t have in different genders (p>0.05), polymorphism also have no significant effect on expression quantity (p>0.05); on the aspect of expression quantity and meat quality, they are significant positive correlation (p<0.05), but there is no significant correlation with shear force and carcass weight, which mean enhancing the expression quantity of Myf5gene is conducive to increase of protein content but have no influence on shear force and carcass weight.The study identified the SNPs and haplotype which associate with the meat quality, and establish the method to detect genotype and haplotype of Myf5gene, In addition this study analysis the distribution of genotype and haplotype, the influence of Myf5gene polymorphism and expression level on meat quality, which lay a foundation for the genetic effect research of other canditate genetic. |
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