Among the major criticisms is the focus on “usual suspect” candidate genes in the serotonin or dopamine pathways (e.g., SLC6A4 or MAO-A) (Dick et al., 2015). Thus, the field is in need of answers to the question of which SNPs are worth carrying forward into studies of G×E using measured genotypes. One way to answer this question is to examine whether certain types of SNPs (based on genomic information) are overrepresented among SNPs with G×E effects. Thus, in an effort to move away from the candidate gene approach, we tested the exploratory hypothesis that SNPs in regulatory regions would be more likely to have significant G×E effects. We believed DHS SNPs would be enriched for G×E interaction effects given that the DNA variants in DHS regions may be more likely to affect the chromatin structure around a gene that determines whether the DNA is accessible to transcription factors (i.e., the proteins responsible for transcribing DNA to RNA and determining gene expression levels) (Cockerill, 2011). Environmental exposures are known to affect epigenetic processes, and can further drive gene expression or repression
