Fly clocks

As a result of the combination of classic genetics, modern molecular biology, and a remarkably precise behavioral assay, studies in Drosophila have generated an explosion in our understanding of the basic molecular mechanisms of circadian rhythms. Furthermore, the identification of Drosophila clock genes has led to the isolation of the mammalian counterparts, including some from humans. It is probably only a matter of time before alterations in the structure or expression of these genes is intimately linked with diseases thought to be caused by clock defects. This chapter outlines the monumental contributions of forward genetics in mice as well as in flies to our understanding of the molecular basis of circadian rhythmicity.