Research on gene-environment interactions is inherently interdisciplinary; it sits at the intersection between genetics and psychology. However, this perspective has not been embraced to the extent that it could be, and (in my opinion) must be, in order to do really good research in this area. Most of the gene-environment interaction research in psychology has been limited to the “usual suspects”—purportedly functional polymorphisms in MAOA, 5-HTT, DRD4, and a few others (Belsky et al. 2009). However, the evidence for those polymorphisms truly being functional is often ambiguous (Cirulli & Goldstein 2007). In addition, in the field of genetics, we would never test a single marker in a gene in order to make conclusions about the relevance of that gene in a given genotype. Rather, with data from the human genome project and the HapMap project, we now know something about the structure of most genes in the human genome (Manolio et al. 2008). Further, there are many polymorphic markers available across most genes of interest. It is possible that multiple locations in a gene could have various forms that lead
