Chunk #73 — III. Specific Genes for Aggressive Behavior: Findings from Molecular Genetic Studies — A. G × E interaction involving specific genes for aggressive behavior
Advances in the field of molecular genetics have also made it possible for researchers to identify G × E interactions much more specifically. One of the most influential studies examining G × E in antisocial and aggressive behavior is Caspi et al., (2002), a famous study from 2002. The relationship between a functional polymorphism in the MAO-A gene encoding the neurotransmitter-metabolizing enzyme and early childhood maltreatment was examined in the development of antisocial behavior in males. A significant G × E interaction was detected, in that maltreated boys with a genotype conferring low levels of MAO-A were found to be more likely to later develop antisocial problems, including conduct disorder, adult violent crime, and antisocial personality disorder, than maltreated boys who had a genotype conferring high levels of MAO-A (Caspi et al., 2002). So far, there have only been a few replications of this important finding (Foley et al., 2004; Kim-Cohen et al., 2006; Nilsson et al., 2006). For example, Kim-Cohen et al. (2006) found that the MAO-A polymorphism moderated the development of psychopathology after experiencing physical abuse in a
