Fig. 1: A diagram of causal and associated genes.
From: A comparison of the genes and genesets identified by GWAS and EWAS of fifteen complex traits
A causal gene is one where the product of that gene affects the trait of interest and in this study, we are assuming that SNPs identified in relation to a trait will affect these genes or tag SNPs that do (SNP-G). An associated gene is one where the product of that gene correlates with the trait of interest, but may not affect it. In this study, we are assuming that CpG sites identified in relation to a trait will map to these genes (CpG-G). The diagram shows how a gene product may be correlated with a trait: 1. by affecting the trait, 2. by sharing a common cause with the trait (confounding), 3. by being affected by the trait (reverse causation). A geneset may be composed of causal and associated gene products. U = confounder.
