Linkage peaks with LOD scores greater than 2.0 were found on chromosomes 1p, 1q, 3q, 5q, 6p, 20p, and Xq. The major peaks, with the exception of those found on 20p and Xq, were found in regions where previous studies have reported linkage for alcohol-related traits (see Table 3), with our best finding confirming linkage reported for chromosome 6 by Hill et al (2004). Similarly, a number of smaller linkage peaks on 12q and 21q (with LOD scores between 1.5 and 2.0), were found to be in regions previously associated with measures of alcohol dependence (Ma et al., 2005). In contrast to the present study, the earlier studies examined samples selected for family history of drinking problems, with most utilizing data from the Collaborative Study on the Genetics of Alcoholism (COGA) sample (Agrawal et al., 2007; de Andrade et al., 2005; Dick et al., 2002; Ma et al., 2005). As shown in Table 3, proposed candidate genes for alcoholism (e.g. AGT, CARTPT, OPRD1, PIK3R1, and PDYN ) can be found in the regions of interest.
