Genome-wide Association Analysis In Simmental Cattle And Xuelong Black Cattle Population For Partial Carcass Traits

With the rapid development of genotyping techniques,genome-wide association analysis（GWAS）has become a powerful method for mapping QTL related to important economic traits in beef cattle.A large number of candidate SNPs have been found,which are significantly related to important economic traits.However,previous studies have found that some significant SNPs found in one beef cattle group may not be detected in another.In China,there are various cattle groups while their population sizes are relative small.Identification significant SNPs or major genes by integrating multiple varieties of data have become a hot research topic in current yearsWe performed GWAS using 770K genotyped SNPs in 1217 Simmental cattle and 476 Xuelong Black cattle established by our team.In our study,we first used the compressed mixed linear model（CMLM）to identify major genes associated to knuckle,biceps and shank of beef carcass traits in each group.And then,genome association analysis was carried out based on two mixture groups,the summary of results were presented as follows:1.In Simmental cattle,seventeen significantly associated SNPs were found,which are located on BTA6,BTA14 and BTA15.Interestingly,one SNP named BovineHD1400007259(p<10^-8)within the well-known gene region PLAG1-CHCHD7 on BTA14,was found to govern variation of the knuckle,biceps and shank traits.The SNP accounted for 8.6%of phenotypic variance for biceps.2.In Xuelong Black cattle,seventeen significantly associated SNPs were found,which are associated with knuckle,biceps and fleat stick.These significant SNPs embedded in 11 genes.One pleiotropic quantitative trait nucleotides,named Bovine HD1400012244,BovineHD1400006323,BovineHD1400015773,BovineHD1400015773,BovineHD1400013403 and BovineHD1400013205 on BTA14,were found related to govern biceps.3.The result of GWAS in mixture group showed that there was no significant SNP associated to biceps,while the most significant SNP BovineHD1400011574 were found at BTA14（P-value=2.23E-06）.In conclusion,we proposed that the region with the two significant SNP,BovineHD1400007259 lo cated in PLAG1 and Bovine HD1400012244 on BTA14,was associated with governing biceps as a majo r gene or QTL.