an experimental study focusing on behavioral mechanisms of alcohol reward in a sample of heavy drinkers has shown that compared to A-allele homozygotes, G-allele carriers report greater subjective reinforcement from alcohol in the laboratory (Ray and Hutchison, 2004). Similar results were obtained in a naturalistic study of the effects of alcohol(Ray et al., 2010c). A study of non-human primates has demonstrated that male macaques carrying the SNP that is homologous to the Asp40 allele displayed increased alcohol-induced stimulation, consumed more ethanol, and exhibited increased ethanol preference(Barr et al., 2007).
