Genetic Effects And MRNA Expression Of KCNJ12 Gene In Three Chinese Cattle

Chinese cattle has some excellent qualities such as strong adaptability,good meat quality and crude feed tolerance,the high strength selection cultivation is feasible way to cultivate the breeds of beef cattle with Chinese characteristics in a relatively short period of time,but the traditional method with long breeding cycle,is susceptible to environmental influenceandit is difficult to quickly cultivate the genetically stable breeds of Chinese beef cattle with excellent economic traits to meet the needs of people.single nucleotide polymorphisms(SNPs)can be used as markers for poultry and livestock breeding,and has great potential for beef cattle breeding.At present,a large number of genetic variants affecting the important economic traits of poultry and livestock have been detected,which provide a theoretical basis for breeding improvementd.KCNJ12 gene expressed widely in cardiomyocytes and neurons,plays an important role in tumor therapy and muscle movement regulation.In addition,it is found that KCNJ12 gene has a certain correlation with bovine body size traits in the current genome-wide association analysis.However,the study of SNPs in KCNJ12 gene has not been reported up to now.Therefore,in this study,by the PCR-RFLP and Tetra-primer ARMS-PCR we analyzed the four SNPs loci of the KCNJ12 gene in three Chinese cattle breeds: JinNan cattle,XiaNan cattle and PiNan cattle.And the gene expression of different tissues in QinChuan cattle was obtained through Real-time quantitative PCR.The main results of this study are as follows:1.Four SNPs were detected in the KCNJ12 gene from Chinese cattle: SNP1:g.35992774 T>G;SNP2:g.35953919 A>G;SNP3:g.35989944 T>C;SNP4:g.35956326 G>A.Specifically,SNP3 was located in third exon of KCNJ12 gene,the allele mutation(T >C)resulted in the mutation of amino acid from the cysteine mutation to arginine.2.In this study,the polymorphism information content of the three Chinese cattle breeds showed that all the four loci were in moderate polymorphism(0.25<PIC<0.5).Chi-square test showed that four SNPs in the PiNan cattle and SNP2,SNP3,SNP4 loci in Xianan cattle were in Hardy-Weinberg inequilibrium(P<0.05);and SNP1,SNP3 of JinNan cattle,SNP1 of XiaNan cattle were in Hardy Weinberg equilibrium(P>0.05),indicated that improving PiNan cattle varieties has broken the trend of the original genetic balance,this variation has important research value in genetics and breeding.3.by The association analysis of SNP1 from three cattle breeds showed that it was significantly correlated with body height in PiNan cattle(P< 0.05),meanwhile it was extremely significantly correlated with body length and chest circumference(P< 0.01);SNP1 was correlated with the Height at hip and Rump length cross in JinNan cattle and Height at hip cross in Xianan cattle(P< 0.05).thebody length and chest girth in JinNan cattlr and chest girth in XiaNan cattle was highly significantly correlated(P< 0.01).4.Correlation analysis of SNP2 showed that in JinNan cattle,body height,chest circumference and the rump length had significant relation with the mutation in SNP2(P< 0.05,P< 0.01),;in the XiaNan cattle it hadhighly significant correlation with body height,body weight and height at hip size traits(P< 0.01);All the growth trait such as body height,body length,and chest circumference were significantly correlated with SNP2,what's more,The individuals with the allelotype GG had more desirable phenotype than others with allelotype AG and AA.5.Correlation analysis between SNP3 and three cattle breeds showed that chest circumference was significantly correlated with the genotype(P< 0.05)and it was extremely significantly correlated with body height and cross height in JinNan cattle(P< 0.01);and SNP3 test correlation analysis in XiaNan cattle body traits found that SNP3 was extremely significantly correlated with the chest,abdominal circumference and body weight(P< 0.01);and the body height and rump length were significantly correlated(P< 0.05),and body length,cross height and chest circumference and hip width were extremely significantly correlated in PiNan cows(P< 0.01).6.SNP4 mutations in JinNan cattle were significantly correlated with body length and chest girth(P< 0.05);In XiaNan cattle,chest circumference and waist circumference were significantly correlated(P< 0.05,P< 0.01)();All the growth traits except body height in PiNan cows were significantly correlated with SNP4(P< 0.01,P< 0.05)().7.Quantitative analysis in QinChuan bovine tissue samples found gene expression of skeletal muscle was in the highest level.in all the six fetal bovine muscle tissues.