9317699 Sullivan Basic and Applied Aspects of this Research: This research uses a favorable model system, a duplication of the Adh gene in certain species of Drosophila, to understand the causes and outcomes of important molecular genetic events, which have occurred during the evolution of this group of insects. Understanding of these events is central in formulating hypotheses regarding the organization and evolution of the genome. Currently, there is substantial interest in determining the structure of several genomes including that of humans. A knowledge of genome structure offers the hope of therapeutic approaches being developed for human genetic diseases. This work is based on the premise that if one wishes to understand the structure of the genome, then one will have to learn how the genome was put together and the mechanisms which control its assembly.