analysis. Multidimensional scaling and cluster analysis showed that for two-bottle choice preference drinking, morphine and ethanol were similar in their pattern of strain differences, but different from diazepam and pentobarbital. This finding was not anticipated based on the pharmacological classes to which these drugs belong (pharmacology alone would have predicted similarity of genetic control across the three drugs sharing strong effects on GABA-A receptors, i.e., ethanol, diazepam and pentobarbital). Data from the literature for a series of sweet and bitter tastants without known pharmacological effects were also examined. Preference for the tastants was similar to drug preferences only in the case of ethanol, where the sweet tastants (sucrose, saccharin) were significantly genetically similar to ethanol preference drinking across strains. This trend was strongest for the 3% ethanol concentration, and less evident for 6 and 10% ethanol. This is consistent with the hypothesis that sweet taste preference drinking partially contributes to ethanol preference drinking in mice, especially at the lower ethanol concentrations (Belknap et al. 1993; Boughter and Bachmanov 2007).
