To investigate linkage for phenotypes derived from the EEG variables and the latent variables, we formed several phenotypes using principal components analysis to summarize collections of variables. We used the first principal component derived from all 13 EEG variables, and also the first principal component derived from alcoholism and latent variables. The comparison of the linkage results for these two outcomes is given in Figure 3. There is one region in the neighborhood of 250 cM on chromosome 2 that shows significant linkage with both of the principal component derived phenotypes. While a peak around 100 cM is present in both, it is only significant with the latent variable prinicipal component phenotype.
