As described above, multiple selective breeding programs have been developed for rat line-pairs differing in alcohol-preference scores. The development of multiple line-pairs was implicitly based on the hypothesis that if a characteristic associated with high, or low, alcohol consumption was observed in more than one line-pair then the probability of this characteristic being associated (positively or negatively) with a genetic predisposition for alcohol abuse is heightened. The development of the replicate pair of HAD vs. LAD rat lines was based explicitly on this hypothesis. The rat line-pairs discussed herein were developed in the 60’s, 70’s, and early- to mid-80’s. Since then, it has become increasingly clear that alcoholism is a heterogeneous disorder with multiple possible antecedents and trajectories. Thus, experiments directly comparing multiple rat line-pairs are relatively recent and very few. These studies are important because they may delineate multiple typologies within this collection of animal models for alcoholism, and this would provide some face validity for the line-pairs regarding the clinical picture.
