4 [Edenberg et al., 2004, 2006, 2007]. In fact, several other genes have been detected in the vicinity of the chromosome 7 peak in COGA [Hinrichs et al., 2006; Wang et al., 2004, 2007], though these were located outside the 2 LOD support interval. This pattern of results may also reflect the fact that the localization of linkage peaks is known to be imprecise [Roberts et al., 1999]. Accordingly, we made the decision here to take advantage of the existent data across chromosome 2 to test for association. This allowed us to evaluate the location(s) of associated genes with respect to the primary linkage peak. It also allowed us to address the imprecise nature of linkage peaks, the hypothesis of the involvement of multiple genes in the region (some of which may be missed by narrowly targeting the region just around the peak), and the evidence for linkage to alcohol dependence-related phenotypes across chromosome 2, suggesting there may be relevant susceptibility genes at multiple locations across the chromosome.
