The Department of Pharmacology in collaboration with the former Alcohol Research Center (ARC) is in a unique research position because its long history of achievement in classical genetics (development of selected lines and inbred strains of mice) is now proving critical to new molecular genetic approaches. In particular, lines of mice selected for differences in the acute actions of ethanol (Long and Short Sleep) and for differential development of acute tolerance (High and Low Acute Functional Tolerance) provide an opportunity to define the genes that are responsible for these different actions of ethanol. Pharmacology faculty have used the Quantitative Trait Loci (QTL) method to delineate chromosomal regions that contain these genes. Soon, these regions will be narrowed to allow the serious gene “hunting” that will, it is hoped, lead to the first identification of genes responsible for alcohol action. Once identified, the role of these genes in human alcoholism can be determined. Several strong possiblities have been identified by this process.