The Correlation Analysis Research Between MTOG,CAPN1 And MSTN Gene Polymorphism With Meat Quality Traits In Yili Horse

In order to study the polymorphism of MYOG,CAPN1 and MSTN genes in Yili horses and their effects on meat quality traits,38 Yili horses were used as subjects.PCR polymorphism and DNA sequencing technology were used to analyze the polymorphisms and population genetics of the target genes.The meat quality of indexes deltoid muscle,latissimus dorsi muscle,triceps brachii muscle,external oblique muscle and gluteus medius muscle were measured,including shear force,water loss rate,cooked meat rate,cooked meat rate and muscle fiber cross-sectional area.The differences of meat quality indexes among different genotypes were analyzed by SAS software,and the favorable mutation sites were found,which provided a preliminary basis for molecular breeding of meat quality traits of Yili horse,The results are as follows:(1)Five mutations were detected in exon1 of MYOG Gene in Yili horse,including SNP1(g.31187343A>C),SNP2(g.31187333G>A),SNP3(g.31187132C>T),SNP4(g.31187105C>G)and SNP5(g.31187099C>T).SNP1 was missense mutation,other sites were nonsense mutation,SNP3 and SNP4 were moderate polymorphic sites,SNP1 and SNP2 were low polymorphic sites,all four sites were in Hardy-Weinberg equilibrium.Results of difference analysis: SNP1 and snp4 showed strong linkage disequilibrium,and there were three genotypes of AACC,accg and AACG,among which the genotypes of latissimus dorsi,lateral oblique abdominis and gluteus medius were significantly lower than those of AACC(P<0.05).(2)SNP6(g.28970528T>A),SNP7(g.28972795T>A)and SNP8(g.28972849A>C)were detected in exon 5,intron 9 and exon 10 of CAPN1 gene in Yili horse,respectively.SNP6 and SNP8 were missense mutations and SNP7 were intron mutations.The three mutation sites were all low polymorphic and in Hardy-Weinberg equilibrium.Results of difference analysis: SNP6 locus at genotype was significantly lower than TT genotype in water loss rate(P<0.05),deltoid and abdominal external oblique muscle crude fat at genotype was significantly higher than TT genotype(P<0.01),arm triceps shear at genotype was significantly lower than TT genotype(P<0.01),The water loss rate of latissimus dorsi,exotropis abdominis and gluteus medius at SNP7 locus was significantly lower than TT genotype(P<0.05),cooked meat rate of exotropis abdominis and gluteus medius at genotype was significantly higher than TT genotype(P<0.05),crude fat and muscle fiber density of exotropis abdominis at genotype was significantly higher than TT genotype(P<0.05),and muscle fiber diameter was significantly smaller than TT genotype(P<0.05).SNP8 deltoid muscle water loss rate AC genotype was significantly lower than AA genotype(P<0.05).The deltoid water loss rate of snp8 genotype AC was significantly lower than that of AA genotype(P<0.05).(3)SNP9(g.66605255T>C)was detected in exon 3 of MSTN in Yili horse,which was a synonymous mutation with low degree of polymorphism and in Hardy-Weinberg equilibrium.Results of difference analysis: the CT genotype of deltoid muscle and external oblique muscle water loss rate was significantly lower than TT genotype(P<0.05),and the CT genotype of deltoid muscle and middle gluteal muscle shear force was significantly lower than TT genotype(P<0.01).Conclusion: among SNP1 and SNP4 genotypes,AACG genotypes,SNP9 CT genotypes and SNP6 at genotypes have low shear stress;SNP7 at genotypes have high cooked meat rate;SNP6 and SNP7 at genotypes have high crude fat;SNP6 and SNP7 at genotypes,SNP8 AC genotypes and SNP9 CT genotypes are available SNP7 mutant at genotype can be used for small muscle fiber diameter and high muscle fiber density,The above loci and genotypes of three target genes can be selected in molecular selection of Yili horse meat quality traits.