Studies On The Genetic Effect Of MSTN, MyoD Family And Smad3 Genes And Their Expression Characterization In Bian Chicken

In the first part of the present study, PCR-SSCP and PCR-RFLP methods were used to detect the SNPs and genetic paraments of the MSTN, MyoD family and Smad3 genes in seventh and eighth generations of Bian chicken. In the second part, we analyzed SNPs relationship with growth traits in seventh and eighth generation of Bian chicken. As well, we analyzed the effects of combined genotypes of four genes and MSTN gene on growth traits and and carcass traits. And in the third part, the developmental pattern of MSTN, MyoD family and Smad3 mRNA expression in breast and leg muscle of Bian chickens were determined by relative quantitative RT-PCR. The main results were as follows:1. PCR-RFLP method was used to detect the polymorphism of G2283A loci in MSTN gene, and it was a reasonably informative locus. Correlation analysis suggested that the loci had significant effect on growth and carcass traits of Bian chicken (P<0.05 or P<0.01).2. The all exons with parts of intron sequences of MyoD genes were screened in the Bian chicken. Four mutations were detected in the MyoD gene. One mutation (T576C) was located in exon 1 and a synonymous mutation. Three mutations were located in intron 3. MD-3 and MD-4 loci were slightly informative locus and disagreement with Hardy-Weinberg equilibrium (P<0.05) in seventh and eighth generation of Bian chicken. Correlation analysis suggested that the MD-3 and MD-4 loci had significant effect on growth traits in seventh generation of Bian chicken (P<0.05 or P<0.01). AA/DD and AA/CC were advantage genotype combination between MD-3 and MD-4 loci. In slow growth group of Bian chicken eighth generation, the MD-3 loci had significant effect on growth and carcass traits in (P<0.05 or P<0.01), the MD-4 loci had significant effect on growth traits (P<0.05 or P<0.01). Between different groups of Bian chicken eighth generation, the genotype combinations effect of different loci between MyoD and MSTN gene for production traits was greater than the effect of a single MD-3 or MD-4 loci, the main was the strain effects.3. Two mutations were detected in the MyoG gene. they (T2827C and G2957A)were located in exon 3 and synonymous mutations. MG-5 locus was highly informative locus and agreeent with Hardy-Weinberg equilibrium(P>0.05) in seventh and eighth generation of Bian chicken. Correlation analysis suggested that the MG-5 locus had significant effect on growth traits from six to ten week in seventh generation of Bian chicken (P<0.05). In all groups of Bian chicken eighth generation, the MG-5 locus had no significant effect on growth and carcass traits (P>0.05). Between different groups of Bian chicken eighth generation, the genotype combinations effect of different loci between MyoG and MSTN gene for production traits was greater than the effect of a single MG-5 locus, the main was the strain effects.4. Three mutations were detected in the Myf5 gene. They (C238、G264A and A532G)were located in exon 1 and synonymous mutations. MY5-1 locus was highly and reasonably informative locus in seventh and eighth generation of Bian chicken, respectively. MY5-3 locus was highly informative locus and agreement with Hardy-Weinberg equilibrium (P>0.05) as the same as MY5-1 locus in seventh and eighth generation of Bian chicken. Correlation analysis suggested that MY5-1 and MY5-3 loci had significant effect on growth traits in seventh generation of Bian chicken (P<0.05 or P<0.01). HH/NN and HJ/NN were advantage genotype combination between MY5-1 and MY5-3 loci. In different growth group of Bian chicken eighth generation, the MY5-1 and MY5-3 loci had significant effect on growth and carcass traits (P<0.05 or P<0.01), Between different groups of Bian chicken eighth generation, the genotype combinations effect of different loci between Myf5 and MSTN gene for production traits was greater than the effect of a single MY5-1 or MY5-3 loci, the main was the strain effects.5. One mutation (A57099T) was detected in the Smad3 gene. It was located in exon 8 and a synonymous mutation. S8 locus was reasonably informative locus and agreeent with Hardy-Weinberg equilibrium (P>0.05) in seventh and eighth generation of Bian chicken. Correlation analysis suggested that the S8 locus had no significant effect on production traits in seventh generation of Bian chicken (P>0.05). In slow growth groups of Bian chicken eighth generation, the S8 locus had significant effect on carcass traits (P<0.05 or P<0.01). Between different groups of Bian chicken eighth generation, the genotype combinations effect of different loci between Smad3 and MSTN gene had significant effect on growth and carcass traits (P<0.05 or P<0.01).6. The developmental pattern of MSTN, MyoD family and Smad3 mRNA expression in breast and leg muscle of Bian chickens were studied. The results showed that the G2283A locus of MSTN gene had significant effect on the expression of MSTN gene in breast and leg muscle of Bian chickens (P<0.05 or P<0.01). The expression level of MyoD gene It is a positive relationship with the expression level between MyoD gene in leg muscle and MSTN gene and it is a negative relationship with the expression level between MyoD gene in breast muscle and MSTN gene. The different genotype combinations of MD-3 loci in MyoD gene and MSTN gene had significant effect on the expression level of MyoD gene (P<0.05). The different genotype combinations of MD-4 loci in MyoD gene and MSTN gene had no significant effect on the expression level of MyoD gene (P>0.05). It is a negative regulatory relationship with the expression level between MyoG and MSTN gene. The different genotype combinations of MyoG and MSTN gene had significant effect on the expression level of MyoD gene (P<0.05 or P<0.01). It is a negative regulatory relationship with the expression level between Myf5 and MSTN gene. The different genotype combinations of Myf5 and MSTN gene had significant effect on the expression level of Myf5 gene (P<0.05 or P<0.01). It is a positive relationship with the expression level between Smad3 and MSTN gene. The different genotype combinations of Smad3 and MSTN gene had significant effect on the expression level of Smad3 gene (P<0.05 or P<0.01).