The dominant effect is a kind of non-additive effects due to the interaction between alleles at the same locus. Quantitative traits such as growth traits in farm animals have been found to be influenced by dominance effects. However, dominance effects are usually ignored in the GWAS of complex traits for farm animals. In this study, we performed GWAS and genetic parameters estimation for two growth traits adjusted age at 100 kg (AGE) and adjusted backfat thickness at 100 kg (BF) of 4,328 Large White pigs. Our results showed significant non-zero variances for dominance effects to these two growth traits. Using a GWAS model accounting both additive and dominance effects, we identified seven additive and two dominance significant SNPs for AGE. For BF, seven genome-wide significant additive SNPs were detected, and no significant SNP was found for dominance effects. Meanwhile, we identified a candidate gene CPPED1 associated with AGE near a dominance association signal. Additionally, seven important functional genes were further identified to be associated with AGE or BF. Overall, the newly detected significant SNPs and newly identified candidate genes in our study have the potential to be applied to the future pig breeding program.
This work was supported by the Beijing Natural Science Foundation (No. 6192010), Beijing Science and Technology Commission (Nos. Z191100004019009, Z201100008020019), Jinxinnong Animal Science Development Foundation for China Agricultural University.