Genome-Wide Association Studies for Immune Related Traits in Pigs

Hematological indices, lymphocytes and cytokine are the major components of immune system and play pivotal roles in animal immune capacity and disease resistance. In our study, we carried out genome-wide association studies (GWAS) using Illumina porcineSNP60k BeadChip for immune responses in piglets for 18 hematological traits (seven leukocyte traits, seven erythrocyte traits, and four platelet traits), seven lymphocyte traits (the proportions of CD4+, CD8+, CD4 + CD8+, CD4 + CD8−, CD4−CD8+, CD4−CD8− and the ratio of CD4+ to CD8+ T cells) and three cytokine traits (INFG, IL10 and INFG/IL10) in two experimental populations which were stimulated with classical swine fever vaccine and polyinosinic-polycytidylic acid (Poly I:C), respectively. For the piglets stimulated with classical swine fever vaccine, in total, 165 chromosome-wise significant SNPs were identified for the traits considered, of which 12 reached genome-wise significance level. While for the piglets stimulated with Poly I:C, a total of 427 chromosome-wise significant SNPs were detected to be associated with the 28 traits, of which 55 reached genome-wise significance level. Many significant SNPs are located within or close to the immune-related QTL/gene regions reported in previous studies. Our study demonstrated that GWAS would be a feasible way for revealing the potential genetic variants affecting immune traits. Results herein lay a preliminary foundation for further identifying the causal mutations underlying swine immune capacity in follow-up studies.