Study On The Relationships Between Polymorphisms Of Chicken PRKAG3 Gene And Slaughter And Meat Quality Traits

The protein kinase adenosine monophosphate-activatedγ3-subunit(PRKAG3) gene encodes a muscle-specific isoform of the regulatory gamma-subunit of adenosine monophosphate-activated protein kinase,the PRKAG3 gene affects the glycogen content in muscle and hence,meat quality traits in pigs,including ultimate pH,meat colour, water-holding capacity,drip loss,tenderness and cooking loss.So,PRKAG3 gene was considered as a major gene of affecting meat quality traits such as muscle pH,color and water holding capacity,and its nonconservative substitution(R200Q) associated with excess glycogen content in pig skeletal muscle is the reason of causing RN effect.But in different breedings,mutations of PRKA G3 gene maybe accorded with the meat quality.240 chickens from 8 populations(including 5 pure lines and 3 crossbreeds developed by Dahen Poultry Breeding Company and Sichuan Animal Science Academy) were studied. All the data on slaughter traits and meat quality traits were gathered.By using single-strand conformation polymorphism(SSCP) method,the single nucleotide polymorphisms(SNPs) sites in PRKAG3 gene were detected.Molecular biology and statistic genetics methods were used to predict the conformation changing caused by the mutation of SNPs,and to reveal the association between SNPs and traits.The results were as follows:3 SNPs sites in exons of the PRKAG3 genes were determined:PRKAG3-1744, PRKAG3-2698,and PRKAG3-3207.The single nucleotide mutation of PRKAG3-1744 could not cause the translating change from amino acid;while the mutation A to G of PRKAG3-3207 could cause the change from Thr to Ala.But there was no chang in the PRKAG3-2698,because the single nucleotide mutation was in the intron 8.The genetic parameters were calculated,and the results showed:PRKAG3-1744, PRKAG3-2698 and PRKAG3-3207 SNPs sites all had intermediate Polymorphism Information Content(0.25＜PIC＜0.5).PRKAG3-1744 PIC=0.353,PRKAG3-2698 PIC=0.349,PRKAG3-3207 PIC=0.353.Theχ~2 agreement test showed that the PRKAG3-2698 was biased significantly from H-W equilibrium(P＜0.05),but all the other populations were in H-W equilibrium at PRKAG3-1744and PRKAG3-3207 sites.The LSM analysis results showed that PRKAG3-1744 SNPs site influenced Breast Muscle Percentage(BMP) in significantly(P＜0.05).It influenced water and CP value very significantly(P＜0.01),and influenced ash value significantly(P＜0.05).PRKAG3-2698 SNPs site influenced Leg Muscle Weight(LMW) value and Breast Muscle Percentage (BMP) value(P＜0.05).PRKAG3-3207 SNPs site influenced slaughter traits at various level(P＜0.05,P＜0.01),and influenced water and CP value very significantly(P＜0.01).In concluding,the combination of the 3-site genotype CC-GG-GG showed its advantage in Leg Muscle Percentage(LMP),but genotype GC-AA-Aashoued its disadvantage in it.