al. 2011b). Finally, the same authors studied several SNPs in the human ALK gene and showed a nominally significant association between these SNPs and altered physiological and subjective responses to ethanol in humans (Lasek et al. 2011b). Such responses have been proposed as intermediate phenotypes for alcohol use disorders and are likely important in the early stages of the addiction process (Stage 2 in Table 1). This example illustrates how the same gene appears to have an evolutionarily conserved role in mediating analogous pheno-types across three highly divergent species. The stepwise progress of this study illustrates how model organisms in conjunction with gene-pathway data can be used to identify novel genes.
