Effects Of Candidate Genes CAST,PHKG1 On Carcass And Meat Quality Traits In Xuanhe Pigs

In order to reveal the the polymorphisms of calpastatin（CAST）and phosphorylase kinase gamma1（PHKG1）gene and their associations with carcass and meat quality traits in the new developed breed Xuanhe pigs,the single nucleotide polymorphisms（SNP）of CAST and PHKG1 PCR detected by PCR product directly sequencing in 111 Xuanhe pigs.The effects of different genotypes and haplotype combinations of SNPs of the two genes on 6carcass traits,dressing percentage（DP）,carcass straight length（CSL）,average backfat thickness（ABF）,loin eye area（LEA）,ham percentage（HP）,lean meat percentage（LMP）,and 7 meat quality traits,meat color（MC）,marbling score（MS）,p H₁,water loss percentage（WLP）,cooked rate（CR）,drip loss percentage（DLP）and intramuscular fat content（IMF）were analyzed by least square model.The main results were as follows:（1）The SNPs in the exon regions of CAST and PHKG1 genes in Xuanhe pigs was revealed.A total of 10 SNPs were detected in the exon region of CAST gene in Xuanhe pigs.There is one in each of the exon 14,17,28 and 29;there were two in each of exon 1,15 and19,respectively.Among the 10 SNPs,EX1-T315G（Leu/Arg）,EX15-A47G（Lys/Arg）,EX17-C22G（Leu/Val）,EX28-C11T（Thr/Met）and EX29-A54C（Arg/Ser）were missense mutations.A total of 6 SNPs were detected in the exon region of PHKG1 gene,which distributed in the exon 3（2 SNPs）and exon 10（4 SNPs）,and the SNP EX10-C224T（Ser/Leu）was a missense mutation.（2）The genetic diversity of Xuanhe pigs was revealed from the polymorphisms of CAST and PHKG1 gene.The average polymorphic information content（PIC）and heterosygosity（H）of the ten SNPs of CAST gene in Xuanhe pigs were 0.2980（0.2211-0.3710）and 0.3727（0.2531-0.4920）;and the average PIC and H of the six SNPs of PHKG1gene in Xuanhe pigs were 0.1982（0.1248-0.3740）and 0.2335（0.1338-0.4980）,and the average PIC and H of the sixteen SNPs of the two genes were 0.2606 and 0.3205,respectively.It indicated that the genetic diversity of Xuanhe pigs was relative abundant.（3）The association CAST gene polymorphism with carcass and meat quality traits in Xuanhe pigs was revealed.The SNP EX28-C11T in the exon 28 of CAST gene of Xuanhe pigs was significantly associated with LEA and HP（P<0.05）;significant associations were showed that EX1-T315G and EX1-C316T with MS and WLP,EX14-T27C,EX15-A12G and EX15-A47G with MC and DLP,EX17-C22G with WLP,EX28-C11T and EX29-A54C with DLP（P<0.05 or P<0.01）.It showed significant effects of different haplotype combinations of the SNPs on all the six carcass traits and three meat quality traits,MS,p H₁and IMF（P<0.05 or P<0.01）.However,the specific effects of the genotypes and haplotype combinations of CAST gene might be various for different traits.（4）The association of PHKG1 gene polymorphism and carcass and meat quality traits in Xuanhe pigs was revealed.Sinificant associations of SNPs of PHKG1 gene in Xuanhe pigs were identified that EX3-A43G with DR and HP,EX3-C55T,EX10-C132T and EX10-C213T with DR,EX10-C224T with LMP,EX10-T27C with CR,EX3-C55T,EX10-C132T and EX10-C213T with IMF（P<0.05 or P<0.01）.It showed significant effects of different haplotype combinations of the SNPs on five carcass traits,DR,ABF,LEA,HP and LMP,and four meat quality traits,MC,p H₁,WLP and IMF（P<0.05 or P<0.01）.The effects of the genotypes and haplotype combinations of PHKG1 gene on the carcass and meat quality traits were also various for different and trats.