To assess potential genetic correlation between a prospective index of LR and either of these endpoints in rodents, we examined two types of evidence (Crabbe et al. 1990). First, there are published data on several inbred strains of mice for two-bottle alcohol preference drinking (Phillips et al. 1994;Belknap et al. 1993a;Wahlsten et al. 2006) and withdrawal severity (Belknap et al. 1993b;Crabbe 1998;Metten, Crabbe 2005). The extent to which strain mean values for these targeted traits correlate with putative low response measures estimates the degree of genetic co-determination of the traits. Second, there are numerous rat lines (P, HAD-1, HAD-2, AA, sP, mSP, and UChB - See Table 1) that have been selectively bred for high alcohol preference, using virtually identical methods [for reviews, see (Bell et al. 2006;Ciccocioppo et al. 2006;Colombo et al. 2006;Quintanilla et al. 2006;Sommer et al. 2006)]. These have been compared with their counterpart lines bred for low drinking (NP, LAD-1, LAD-2, ANA sNP, UChA) on a number of behaviors. We reason that if several of these pairs of rat lines differ consistently on a behavioral response
