Unravelling regulatory variants affecting gene expression in four porcine tissues

The aim of this work was to identify functional variants potentially associated to complex phenotypes, to improve genomic selection. In this study, we combined genomics, transcriptomics and epigenomics data. First, we genotyped 100 pigs with the high-density genotyping array (with 660K markers). Then, we generated RNA-seq data on these animals in 4 biologically divergent tissues: liver, spleen, lung and muscle. We performed an expression GWAS (eGWAS) resulting in the identification of over 150,000 significant associations in each of the tissues. We were able to detect over 1,300 genes that showed a significant eGWAS associations. We also found an enrichment of eGWAS hits within regulatory elements such as enhancers and promoters, which indicates their pivotal role as drivers of phenotypic variation and thus are of highly relevance towards understanding the genetics of complex traits.