“…Since striatal dopamine signaling is directly influenced by dopamine transporter (DAT) availability (Shen et al, 2004, e.g., Giros et al, 1996, Heinz et al, 1999), it has been hypothesized that genetic variation in the gene encoding the DAT ( DAT1/SLC6A3 ) contributes to differences in reward processing (Lohoff et al, 2010, Dreher et al, 2009, Hahn et al, 2011). While several studies have indeed found associations of SLC6A3 variation with various alcohol use disorder phenotypes and endophenotypes (Ma et al, 2016, Ray et al, 2014, Wernicke et al, 2002, Le Strat et al, 2008, Gorwood et al, 2003), other studies were unable to replicate results (e.g., Du et al, 2011, Kohnke et al, 2005, Xu and Lin, 2011). Genetic variation is one important factor influencing interindividual differences in reward processing; however, it is likely that other mechanisms affecting DAT expression or function may also contribute.…”