Linkage analysis of the 12 alcohol dependence symptoms also provided insights into the relations between specific genomic regions and the alcohol dependence diagnosis. For example, the linkage evidence for the chromosome 1 locus at 11 cM was driven by a broad range of symptoms including spending significant time drinking, an inability to reduce drinking, experiencing withdrawal symptoms, and reduced social and occupational functioning due to drinking. In contrast, the linkage evidence for the chromosome 8 locus was driven by a much narrower range of symptoms including an inability to reduce drinking and experiencing withdrawal symptoms. Further, several of the individual symptoms showed higher LOD scores at a given locus than the alcohol dependence diagnosis itself (max LOD score for either alcohol dependence diagnosis = 2.42 vs. max LOD score among alcohol dependence symptoms = 4.22).
