The 10% ethanol solution was offered for 4–10 days. As shown in the left panel of Fig. 1, chromosome 2 congenic data supported QTL capture on the C57BL/6J background (introgression of the DBA/2J region reduced ethanol consumption), but not on the DBA/2J background (introgression of the C57BL/6J region did not significantly increase ethanol consumption). Similar results were obtained in chromosome 9 congenic mice (Fig. 1, right panel). In both cases, the data suggest that a single QTL region was unable to alter the ethanol drinking phenotype on a genetic background that shows extreme avoidance of ethanol.
