Abstract: 【Objective】 The aim of the present study was to explore the polymerization effects of MyoG and MEF2a genes on duck slaughter traits in order to provide a research foundation for further determining the molecular genetic markers related to duck growth traits, also provide a basis of polygene pyramiding breeding of slaughter traits of ducks.【Method】 A total of 240 individuals of Sansui ducks were selected as experimental material in the study, MyoG gene and MEF2a gene were amplificated and had PRC direct sequencing to detect the single nucleotide mutation (SNPs) of all exons of two genes. Base mutation (SNPs) was detected by direct sequencing of the PCR products. GLM statistical model of SPSS 18.0 software was used to analyze the association with different genotypes corresponding to the SNPs MyoG gene and MEF2a gene with Sansui duck slaughter traits. Based on the single gene association analysis results, the polymorphic sites of MyoG and MEF2a genes with significant influence on slaughter traits were employed to build polymerization genotype by using software PHASE 2.0. 【Result】The result showed that eight SNPs were found in MyoG gene and MEF2a gene, and six SNPs were found in MyoG gene and two SNPs were found in MEF2a gene. In all mutations, the G/C mutation in the g.2977G＞C SNP of MyoG gene resulted in the change of codon from GAG to GAC, and the coding amino acid changed from Glu to Asp; While 2 polymorphic site in the MEF2a gene, the G/A mutation at the g.47915G＞A SNP and the G/A mutation at the g.47918G＞A SNP led to codon change from GAA to AAA and GAT to AAT, and the coding amino acid from Glu/Lys and Asp/Asn. The other five SNPs belonged to synonymous mutations, which did not cause the variation of encoding amino acids. Besides, the SNPs fit with Hardy-Weinberg equilibrium except that g.1131C＞T of MyoG and g.47915G＞A, g.47918G＞A of MEF2a gene which were tested by ?2. The results of correlation analysis between polymorphism sites and slaughter traits showed that the SNP of g.1131C＞T and the SNP of g.2204G＞A in MyoG gene had significant influence over the breast muscle percentage, the body weight and eviscerated weight, and the correspondings to homezygote genotype CC and GG were dominant genotypes. The SNP of g.47915G＞A and g.47918G＞A in MEF2a gene affected the eviscerated weight, and the GA genotype individuals belong to dominant genotype individuals. The g.1131C＞T and g.2204G＞A in MyoG gene and g.47915G＞A and g.47918G＞A in MEF2a gene, which relating to slaughter traits (body weight, eviscerated weight, breast muscle rate and eviscerated rate) were selected and the multiple gene polymerizations (interaction) were analyzed, the results showed that after polymerization, the eviscerated rate of eight kinds of aggregated genotype individuals were not significantly different among different genotypes, the mean value of TTGAGA genotype was the highest, followed by CCGGGA genotype. The differences of other three indexes among different genotypes reached a significant level, and weight and eviscerated weight were positively correlated, and the CCGAGA genotype was the highest, followed by CTGGGA genotype; The average rate of chest muscle of CCGGGG genotype was the highest, followed by CCGGGA genotype. The result indicated that the highest main value of genotype of single gene was CC, GG and GA. After two genes combined, CCGGGA genotype in the four indicators was not the optional combination, which showed that there exist interactive effect between MyoG gene and MEF2a gene.【Conclusion】The results revealed that one single molecular marker breeding maybe not good and cannot obtain good result from the interaction of two genes. However, regnant aggregated genotype individuals was not more than enough, more samples should be selected to investigate the aggregated effect of more genes in further study, and to obtain effective molecular markers for poultry breeding.

Key words: MyoG gene, MEF2a gene, slaughter traits, polymerization effect