The characterization of the cellular processes that support learning and memory requires the combination of many different approaches, from the rigorous examination of behavior to the study of the molecular mechanisms that govern plasticity in neurons. These experiments focus on the genetic, behavioral and molecular characterization of the novel Drosophila learning mutant, lightminded. This mutant was isolated in a screen for mutants with affected mushroom bodies, structures in the fly's brain implicated in olfactory learning. More alleles of lightminded will be generated in an attempt to isolate a null allele and provide more lesions of this gene for behavioral analysis. The investigation of learning and memory will extend to an analysis of the components of acquisition and retention, resulting in a behavioral profile that may be related to lightminded's neurobiological phenotype. Finally, in the molecular analysis of this gene, work will focus on identifying the gene product and defining its function in the mushroom bodies of the fly. The objective of this research is to relate the results of these analyses to each other in a way that deepens our understanding of how learning and memory are supported cellular processes that are in turn controlled by the genome.