P rats have been selectively bred for >75 generations for their high drinking phenotype (Li and McBride, 1995; Bell et al., 2006; McBride et al., 2014), and are conceptually analogous to individuals with generations of family history of excessive drinking (i.e., family history positive). As P rats were originally derived from Wistar rats, we opted to use this population (which is “family-history negative”) to assess possible family history effects.
