Genome-wide Association Analysis Of Growth Traits In Ningxia Angus Cattle Based On Dd-RAD Technology

As one of the specialized beef cattle breeds in the world,Angus cattle have been introduced into my country and have been rapidly promoted for breeding due to their excellent characteristics such as early maturation,roughage resistance,strong adaptability and fast growth rate.In Ningxia,the number of Angus cattle is the second largest beef cattle breed after Simmental.In order to understand the changes in growth performance of Angus cattle since its introduction to Ningxia and the progress of growth performance between generations,this study The changes of growth traits of Angus cattle were analyzed from two aspects of different years and different generations.The dd-RAD simplified genome sequencing technology was used to develop SNP markers in the whole genome.The general linear model(GLM)and mixed linear model(MLM)conducted a genome-wide association analysis,obtained SNP loci and candidate genes related to the growth traits of Angus cattle,and used RT-qPCR to verify the expression of the candidate genes.The main research results are as follows:(1)Through the analysis of the phenotype data of Angus cattle in different years and generations,it is found that between 2016 and 2021,except for the primary stage,the body weight,body height,cross height,body oblique length,chest circumference and abdominal circumference of other growth stages vary with the year.The increase of genotype showed a gradual increase trend,and the tube circumference at each stage fluctuated between years;the body height and chest circumference of the second generation in the primary stage were significantly higher than those of the first generation(P<0.05).The body oblique length and abdominal circumference were significantly higher than those of the first generation(P<0.05),and the weight,body height,cross height,body oblique length,chest circumference and abdominal circumference of the second generation at 6 months were significantly higher than those of the first generation(P<0.05).The bust circumference of the second generation at the age of 12 months was significantly higher than that of the first generation(P<0.05).(2)Through genome-wide association analysis,a total of 196 SNPs were identified that were significantly associated with Angus cattle body weight,and 214 SNPs were potentially associated with Angus cattle body weight.Through GO and KEGG enrichment analysis,a total of 16 SNPs were identified with Angus cattle body weight.Candidate genes related to bovine growth traits are AX3,PPARGC1A,PLA2G4A,CALCA,ALX4,MRVI1,CALCBP,LCB1,SLC6A14,LPIN1,GRB10,PDGFD,PTEN,JAK3,LAMA4,COL4A1.(3)It was verified by RT-qPCR that GRB10 and PDGFD genes were expressed in different tissues of Angus cattle at different stages,indicating that GRB10 and PDGFD genes could be potential candidate genes for growth traits of Angus cattle.