In an early transcriptome and RT-PCR confirmatory analysis of the frontal cortex between AA vs. ANA and P vs. NP rats (Worst et al., 2005), it was found that whereas the AA and ANA rats differed in the expression of 6 genes (Munc18, Stx1a, Stx1b, Cacna2d1, Vamp2 and mGluR3) the P and NP rats differed only in the expression of Vamp2. When examining quantitative trait loci (QTL’s) for alcohol preference of high and low alcohol-consuming rat lines, it was found that the QTL’s mediating differences between P and NP rats were located on chromosomes 3, 4 and 8 (Bice et al., 1998; Carr et al., 1998); whereas QTL’s mediating differences between HAD1 and LAD1 rats were located on chromosomes 1, 5, 10, 12 and 16 (Foroud et al., 2000). An initial follow-up study revealed QTLs on chromosomes 5, 10 and 16, but not 12, mediated alcohol preference differences between HAD2 and LAD2 rats (Foroud et al., 2003). A subsequent study revealed that QTLs on chromosomes 10 and 16, but not 5 and 12, mediated alcohol preference differences between HAD2 and
