Variance components linkage analysis of the nicotine dependence diagnosis yielded evidence for linkage on chromosome 2 at 184 cM nearest marker D2S2188 with an associated LOD score of 3.54, which achieved genome-wide significance (point-wise empirical p = .000012) (see Table 1). The parallel relative-pair analysis also revealed a linkage peak in this region at 164 cM nearest marker D2S151 that failed to reach genome-wide significance (All pairs - LOD = 2.98, point-wise empirical p = .00012), but nonetheless, suggested the evidence for linkage to this region was robust across analytic methods. The shift in location of the linkage peaks likely resulted from differences in LOD score calculations across methods given that the same IBD estimates were used for both sets of analyses.
