Linkage analysis of the alcohol dependence diagnosis requiring the temporal clustering of symptoms failed to yield any peaks that achieved genome-wide significance, but four peaks of interest were identified (see Table 2 and Figure 1). The first peak was located on chromosome 1 at approximately 11 cM (LOD = 1.41) with a support interval that extended from the p terminus of the chromosome to 39 cM. The second peak was located on chromosome 2 at 287 cM (LOD = 1.15) with a support interval that extended from 248 cM to the q terminus. The third peak was located on chromosome 8 at 163 cM (LOD = 1.47) with a support interval that extended from 158 cM to the q terminus at 175 cM. The fourth peak was located on chromosome 18 at approximately 48 cM (LOD = 1.27) with a support interval that extended from 26 – 60 cM. Notably, there was no evidence of heterogeneity in LOD scores between families as each pedigree had an estimated alpha, which can be interpreted as the probability of linkage for a given family, that was >0.99 for each peak as estimated by HLOD (Goring, 2002).
