A systematic strategy of gene identification followed by efforts to characterize moderation of the effect associated with that gene can be found in the example of GABRA2, and moderation by parental monitoring. GABRA2 was originally identified by the Collaborative Study on the Genetics of Alcoholism, the largest gene identification project in the area of alcohol dependence (Begleiter et al., 1995), by systematically interrogating GABA receptor genes with evidence for involvement in ethanol related response (Harris, 1999) that were located in a region of linkage identified with both clinical alcohol dependence phenotypes and electrophysiological endophenotypes (Ghosh et al., 2003; Porjesz et al., 2002; Reich et al., 1998). Association between GABRA2 and alcohol dependence was subsequently reported (Edenberg et al., 2004) and replicated by multiple independent research groups around the world using a variety of research designs (Covault, Gelernter, Hesselbrock, Nellissery, & Kranzler, 2004; Enoch, Schwartz, Albaugh, Virkkunen, & Goldman, 2006; Fehr et al., 2006; Lappalainen et al., 2005; Olfson & Bierut, 2012; Soyka et al., 2008). Although there have been failures to replicate (Covault, Gelernter, Jensen, Anton, & Kranzler, 2008; Drgon,
