We focus on identification of genes. Although associations in chromosomal regions that do not contain annotated genes also provide interesting results, the genes that we identify in the present work provide a number of interesting views of addiction. 1) More are represented among cDNAs cloned from brain libraries than is the case for all human genes. While all do not display at least two cDNAs in at least one brain library represented in dbEST, it seems likely that many of the remaining genes are expressed at low levels and/or in small brain regions that are not adequately represented in many of these libraries. 2) The results from dbEST studies of the expression of these genes focus attention on expression in hippocampus, which manifests interesting roles in mnemonic processes in ways that may provide clues to the pathophysiology of human addiction. 3) These genes do not overlap, to extents greater than expected by chance, with genes listed in the Knowledgebase for Addiction Related Genes (KARG), a recent compilation of literature and database information concerning addiction related genes [49]. 4) Gene ontology
