The laboratory is interested in the molecular basis of behavior. The major emphasis, to date, has been on the mechanisms underlying circadian rhythms of rest:activity, using Drosophila as a model system. Our accomplishments in this area include the isolation of the timeless clock gene, the finding that timeless (tim) functions in an autoregulatory loop that lies at the core of the endogenous clock, elucidating the mechanisms that synchronize the clock to light and discovering mechanisms that transmit signals from the clock and produce overt rest:activity rhythms. In addition, we have investigated the role of clocks in peripheral (non-brain) tissues in Drosophila as well as mammals. We recently also initiated studies of other behaviors, such as sleep. We and our collaborators established Drosophila as a model system for sleep research. This genetic model for sleep allows us to address longstanding questions about sleep regulation and function that were previously difficult to tackle. Ongoing work in the laboratory is directed towards understanding the control of physiology and behavior by the clock, the genetic and molecular basis of sleep and, finally, the relationship of the circadian and sleep systems to other aspects of physiology, in particular to metabolism.