To understand how phenotypic variations by gene x environment (GXE) interactions between the circadian clock genes/pathways and light/temperature/diet occur at a molecular level using Drosophila, the fruit flies, as a model system.

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Due to advances in science and technology, our lifestyle in the U.S. has significantly changed from that of 100 years ago. We are not only exposed to excessive food and light, but also, our feeding and sleep patterns are often forced to be irregular and are thus misaligned to our normal biological rhythms. What are the consequences of these lifestyles for health and longevity? How does our diet and feeding time affect our sleep, health, and ultimately, lifespan? Circadian (~24 h) clocks control a wide range of rhythmic physiological and behavioral parameters such as sleep and feeding. Although circadian rhythms are generated by endogenous molecular clocks, they are entrained to external environmental cues such as light, food (both timing and composition), and temperature. Importantly, these environmental factors are among the main sources of phenotypic variation in organismal fitness (such as longevity and stress response), physiology (such as reproduction and metabolic contents), and behavior (such as sleep and feeding). For example, reduction in diet intake without causing malnutrition (diet/calorie restriction (DR/CR)) and low temperature significantly extend lifespan at the expense of fecundity. However, how the circadian clock genes/pathways respond to environmental changes to cause phenotypic plasticity and its impact on short-term and long-term survival and fitness is largely unknown. Molecular genetic mechanisms underlying these gene x environment interactions will be studied using transcriptome / metabolomic analysis combined with RNAi-mediated in vivo functional screen and state-of-the-art molecular genetic tools in Drosophila.