Using short term selective breeding from a more genetically diverse population (heterogeneous stock [HS] animals) derived from four inbred strains (B6, D2, BALB/cJ, LP/J), Hitzemann et al (2009) recently identified seven significant, coincident QTLs on mouse chromosomes 1 (two), 3, 6, 11, 16 and 17 with apparent reciprocal effects on ethanol consumption and acute ethanol withdrawal severity. Previous work using B6D2 populations detected putative reciprocal QTLs for these two phenotypes on chromosomes 1, 2, 4 and 15 that may contribute to the negative genetic relationship between ethanol consumption and acute withdrawal (Metten et al., 1998). Although the selection from HS and B6D2 QTL data appear discordant, this is not necessarily the case, since a QTL detected in one genotype may be ‘silent’ in another, or the loci may have strong epistatic effects (Hitzemann et al., 2009).
