Association Analysis Of SNPs In Candidate Genes With Growth And Carcass Traits In Qinchuan Cattle

Beef cattle industry is an important part of livestock husbandry in China.Improving the growth rate and meat quality of beef cattle is the main breeding goal at present.Growth and carcass traits of beef cattle are typical quantitative traits regulated by multiple genes and their genetic regulation mechanisms are complex.Qinchuan cattle is one of the best local breeds in China because of its excellent adaptability and resistance of roughage.Despite this,Qinchuan cattle have a slower growth rate and a lower meat production compared with other foreign beef cattle breeds.Therefore,there is a great value of using molecular marker-assisted breeding to improve the growth and carcass traits in Chinese local Qinchuan cattle breed.Recent studies have shown that c.*188G>A SNP of AKIRIN2,the g.231054C>T SNP of TTN,the g.70014208A>G SNP of MYBPC1 and the g.1471620G>T SNP of EDG1 have important influence on the beef marbling score in Japanese black cattle.In this study,to investigate the effects of the c.*188G>A SNP of AKIRIN2,the g.231054C>T SNP of TTN,the g.70014208A>G SNP of MYBPC1 and the g.1471620G>T SNP of EDG1 genes on growth and carcass traits in Qinchuan cattle,the 4 SNPs of 350 Qinchuan cattle,24 Luxi cattle,41 Mongolia cattle from Inner Mongolia,50 Mongolia cattle from Mongolia,50 Wuling cattle and 50 Longlin cattle were genotyped using Mass ARRAY and PCR-RFLP.After that,the genetic diversity and association analyses with growth and carcass traits of 4 SNPs in Qinchuan cattle were performed.Meanwhile,the distribution of the well-characterized alleles of the 4SNPs among 11 or 47 beef cattle populations from different countries and regions were compared.Finally,Real-time PCR was used to analyze the correlation between the m RNA expression levels of these genes with intramuscular fat content(IMF)in longissimus muscle of Qinchuan cattle.The results are as follows:(1)No significant departures from the Hardy–Weinberg equilibrium at the 5% level were detected by any test for the c.*188G>A SNP of AKIRIN2,the g.231054C>T SNP of TTN,the g.70014208A>G SNP of MYBPC1 and the g.1471620G>T SNP of EDG1.(2)For the c.*188G>A SNP of AKIRIN2,the SNP genotype had the statistically significant effect on the body length,hip width,chest depth and chest circumference of growth traits(P < 0.05).For the g.231054C>T SNP of TTN,the SNP genotype had the statistically significant effect on the withers height,chest depth and chest circumference of growth traits and back fat thickness of carcass traits(P < 0.05)in Qinchuan cattle.For the g.70014208A>G SNP of MYBPC1,the SNP genotype had the statistically significant effect on the body length,withers height,hip height,rump length,hip width,chest depth and ultrasound loin muscle depth(P < 0.05).For the g.1471620G>T SNP of EDG1,the SNP genotype had the statistically significant effect on the hip width,back fat thickness,ultrasound loin muscle area and intramuscular fat content(P < 0.05).(3)The well-characterized A(c.*188G>A),T(g.231054C>T),A(g.70014208A>G)and T(g.1471620G>T)alleles in Japanese Black cattle were significantly higher than 6 Chinese cattle population.(4)Down-regulations of the AKIRIN2 and TTN genes(P < 0.05 and P < 0.01,respectively)were observed in the Qinchuan cattle group with high IMF content.The expressions of the MYBPC1 and EDG1 were up-regulated in longissimus muscle of Qinchuan cattle group with low IMF content(P < 0.01 and P < 0.05,respectively).These results suggest that the c.*188G>A SNP of AKIRIN2,the g.231054C>T SNP of TTN,the g.70014208A>G SNP of MYBPC1 and the g.1471620G>T SNP of EDG1 might be useful as a molecular marker for growth and carcass traits,and provide scientific evidence for genetic improvement in Qinchuan cattle.