Looking at the individual SNPs (see Table S4), we observe that most top SNPs cluster in the region roughly around 85,500,000 (see Figure S2). This is a region containing large numbers of expression quantitative trait loci (eQTLs; panel C). eQTLs are places in the genome that influence to what extent a gene comes to expression, that is, how much is transcribed to messenger RNA. Only a few SNPs are among the top 10 independent SNPs for more than one phenotype. This suggests that the effects of CADM2 were not driven by one strong causal SNP. Six SNPs were associated with three different (but overlapping) primary phenotypes (sensation seeking, any behavioral/substance addiction, and risk‐taking proneness). Another SNP that was a top SNP more than twice was rs1271459, associated with ever tobacco use, regular tobacco use, and age at first sexual intercourse. SNPs associated with multiple distinct phenotypes might be more central to the functioning of the gene. As an illustration, we looked up this rs1271459. No information was available for this SNP itself, but its proxy rs9820373 is a significant eQTL
