The Genetics of Sleep in Caenorhabditis elegans

Essential functions have preserved sleep throughout evolution, and the molecular pathways controlling sleep are conserved, making model organisms powerful tools for exploring the mechanisms of sleep. Caenorhabditis elegans is a microscopic nematode, which has been leveraged to study many biological processes, including sleep. C. elegans is ideal for mechanistic sleep studies because of their simple, well-defined nervous system, conserved neurochemistry, and genetic tractability. Two distinct sleep states have been the primary focus of C. elegans researchers over the past decade, developmentally timed sleep and stress-induced sleep, because of their similarities to mammalian circadian sleep and sleep during sickness, respectively. Here we review the genetics and molecular signaling pathways that govern these and other sleep states of C. elegans.