Grant: Operating Grant

Sleep and circadian rhythms (24h biological rhythms regulated by an internal biological clock) have a huge impact on human performance, and affect many common diseases. However, despite their importance to human biology and performance, our knowledge of the genes important for human sleep and circadian rhythms is incomplete. The overall goal of this study is to identify genes associated with sleep and circadian behavior, to explore the mechanisms whereby they act, and to apply these findings to the prediction of sleep and circadian rhythms in the real world. To do this, we will take advantage of the observation that sleep and circadian behavior varies between individuals and some of these differences appear to be inherited. We will use actigraphs - wristwatch-like accelerometers - to non-intrusively measure sleep and circadian behavior in several preexisting large groups of volunteers in Ontario and elsewhere. Using already-available genetic data form these same individuals, we will examine for natural gene variants associated with variation in sleep and circadian behavior, and examine the effects of these variants on gene expression. Finally, we will apply our findings to the prediction of sleep and circadian behavior in a community-based population, and to the prediction of stroke timing in individuals who have suffered a stroke. This study has the potential to identify new genes regulating human sleep and circadian behavior, thereby deepening our understanding of human sleep and circadian rhythms. In so doing, it may eventually lead to new treatments and management strategies for shift-work, jet lag, and sleep disruption that have enormous social and medical consequences for millions of Canadians, and may facilitate genetically-guided personalization of school, work, travel and other schedules to optimize human performance.