In alcoholism, as in other addictive disorders, the pathways through which brain chemicals (i.e., neurotransmitters) and other signaling molecules act may also play a role in the development and maintenance of addictive behaviors. For example, researchers using the fruit fly Drosophila melanogaster as an animal model of alcohol sensitivity found that a fly mutant called cheapdate exhibited enhanced vulnerability to alcohol (Moore et al. 1998). This mutant carries a specific allele of a gene important in cellular signaling pathways; consequently, genes involved in this and other signaling pathways would be reasonable choices for candidate genes influencing alcohol sensitivity and possibly alcoholism. (For more information on alcohol-related studies in Drosophila, see the article in this issue by Heberlein, pp. 185–188.) The selection of particular genes for further analysis as candidate genes could be facilitated if some of the potentially important genes were located in DNA regions that could be linked to alcoholism in genome screens.
