Subjects were recruited for participation in studies of the genetics of CD, OD, and alcohol dependence (AD) from the communities around four sites listed above for linkage scan sample plus the University of Pennsylvania. The number of samples recruited at each site for the current study is presented in Supplementary Table 1. Part of the set of samples genotyped at the replication stage overlapped with the samples used for linkage analysis. To obtain an independent sample set for replication study, the overlapping samples (72 CaD cases) were excluded from analysis in the replication stage. Subjects were interviewed with the SSADDA and the diagnosis of CaD was derived based on DSM-IV diagnostic criteria. Most controls were recruited at the same recruitment sites (excluding McLean) and were screened to exclude those with a diagnosis of DSM-IV substance abuse or dependence, and a major Axis I psychiatric disorders. All subjects included in the current study are self-reported AA or EA. Subjects were re-classified as AA or EA on the basis of 41 ancestry informative genetic markers (AIMs) using STRUCTURE, as described previously (20,
