| In this study, we select candidate genes which related to meat quality traits in QinChuan cattle, using bioinformatics methods to predict the structure and function of candidate genes; Analyzed the expression pattern in different tissues of Qinchuan cattle (30±2months of the age at slaughter) by real-time fluorescent quantitative PCR, which to understand regularities of distribution of the candidate genes in different tissues; We have used PCR-RFLP and DNA sequencing to analyze the genetic variations of the candidate genes in Qinchuan cattle and their association with the growth and carcass traits. The main results were showed as following:1Bioinformatics analysis of the candidate genes in Qinchuan cattleWe first used bioinformatics methods to predict the structure and function of candidate genes, the result showed that ApoE gene including1014bp nucleotides, and encoding361amino acids. The instability index of protein is49.32. FAIM2gene including1046bp nucleotides, and encoding316amino acids. The instability index of protein is49.02. At the same time, the protein has seven strong transmembrane helices located at105-128aa,138-160aa,165-187aa,192-214aa,226-245aa,246-271aa and291-313aa. MYH3gene including15823bp nucleotides, and encoding1940amino acids. The instability index of protein is49.79. The structure prediction showed that the protein has adenosine triphosphatase, calmodulin domain and curly spiral structure domain. The hydrophobicity value of the protein showed that parts has the strong hydrophobicity, and showing the protein belong to unstable protein2Expression pattern of the candidate genes in Qinchuan cattleAnalyzed the expression pattern of ApoE、FAIM2、SPP1、MYH3、MYH8、Mtch2and SH2B1in different tissues(Lung, muscle, stomach, sebum, heart, liver, intestine and spleen) of Qinchuan cattle (30±2months of the age at slaughter) by real-time fluorescent quantitative PCR, which reported the expression of ApoE was presented at significantly higher levels in sebum and liver tissues than in other tissues. FAIM2gene was expressed in a wide range of tissues, and with highest expression in the muscle than in other tissues. Expression of SPP1 was presented at significantly higher levels in sebum than in other tissues. Expression of MYH3was restricted to the muscle, lung and sebum, with highest expression in the muscle than in other tissues. Measurable expression was observed in all tissues tested for MY8gene, but the relatively high expression in the spleen was more pronounced in muscle and heart tissues than in other tissues. In addition, mRNA levels of Mtch2and SH2B1gene were expressed in a wide range of tissues and no significant differences were exhibited among the different tissues.3Effects of polymorphisms of candidate genes on growth and carcass traits of bovineWe used the PCR-RFLP and DNA sequencing to detect the SNPs in candidate genes of Qinchuan cattle, a total of17SNPs were found in3genes, and the association between the polymorphisms and growth and carcass traits were analyzed, the result that SPP1、MYH8、 Mtch2、SH2B1genes has no SNPs. ApoE gene have detected two SNPs, they were T'C and C'A, respectively, They were Synonymous mutation. FAIM2gene have detected two SNPs, which were all C'T. MYH3gene have detected13SNPs, they were C'T, C'T, C'T, T'C, C'T, C'T, G'A, C'A, G'C, T'C, G'C, T'C and G'A. Genetic diversity results showed all of them were medium polymorphism.3.1Effects of polymorphisms of ApoE gene on growth and carcass traits of bovineIn the ApoE gene, at locus T1215C, the animals with the CC genotype had heavier slaughter weight than those with the TT and TC genotypes, and the TC and CC genotypes had heavier carcass weight than those with the TT genotype. At locus C2142A, the CC genotype was better than CA genotype, and the animals with the CC genotype had heavier carcass weight than those with the CA genotype.3.2Effects of polymorphisms ofFAIM2gene on growth and carcass traits of bovineIn the FAIM2gene, at locus C3377T, the animals with the CT genotype had greater hip width than those with the CC and TT genotypes, and TT genotype had heavier carcass weight than those with CC genotype.3.3Effects of polymorphisms of MYH3gene on growth and carcass traits of bovineIn the MYH3gene, at locus C1878T, the animals with the CT genotype had greater withers height and heavier slaughter weight than those with the TT genotype. At locus T2010C, the TT genotype was better than the TC and CC genotypes, and the animals with the TT genotype had greater withers height than those with the CC genotype, the animals with the TT genotype had heavier slaughter weight than those with the TC and CC genotypes. At locus G3746C, the animals with the GG genotype had greater body length and withers height than those with the GC and CC genotypes, and GG genotype had greater hip width than those with GC genotype. At locus C7315T, the animals with the CC genotype had heavier slaughter weight than those with CT genotype. The rest of the records of growth and carcass traits had no significant association. At locus T11576C, the individuals with TT genotype had heavier carcass weight than that with TC and CC genotypes, meanwhile the slaughter weight of animals with TT genotype was significant heavier than that of animals with TC genotype. At locus T11698C, the animals with TC genotype had heavier carcass weight than animals with CC genotype, and in term of slaughter weight, the animals with TC genotype were significant heavier than the animals with TT genotype. At G13095A locus, the animals with GG genotype had lighter slaughter weight than animals with GA and AA genotypes, besides, it showed that the carcass weight of animals with AA genotype was significant heavier than that with GG genotype. At C13169T locus, animals with TT genotype had heavier carcass weight than animals with CC genotype. At C13189T locus, the carcass weight of animals with CT genotype was heavier than that of animals with CC genotype. At G13791A locus, it showed no significant difference in any index. At C13975A locus, while the animals with CA Genotype had heavier slaughter weight than CC genotype ones, the hip width of animals with CC and AA genotypes was wider than that of animals with CA genotype. At G17665C locus, the only significant difference was that the animals with GC genotype had heavier carcass weight than individuals with CC genotype.In conclusion, we successfully cloned the candidate genes of Qinchuan cattle, it is useful for the further research on the function of candidate genes in the growth process of Qinchuan cattle. The expression patterns of candidate genes analysis provide a scientific theory on the expression of relative traits. The purpose of this study is to settle the theory foundations on the native breeding work of Qinchuan beef cattle. |
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