WILD_EYES

Natural genetic variation affecting the nervous system is a major influence that shapes us as individuals. However, how small changes in our genomes cause dramatic changes in sensory perception and behaviour is poorly understood. This project is based on our preliminary observations of a surprisingly high level of natural variation in Drosophila melanogaster affecting adult retina photoreceptor neurons and the circadian behaviours. The differentiation program of Drosophila colour photoreceptor neurons is one of the better understood for a sensory system. Yet, there are clear major gaps in our knowledge of how photoreceptors acquire and maintain their functional identities. Similarly, circadian behaviour is one of the first behaviours to be studied genetically. However, many questions remain about its molecular and cellular underpinnings. Among them is how the light information is transmitted from the photoreceptors to the clock neurons to synchronize the circadian rhythms to the day-night cycles resulting from the Earth rotation. We propose to use powerful tools available for the Drosophila model organism 1) to identify the natural genetic variants that affect Rhodopsin expression in colour photoreceptor neurons, and separately, that affect the visual-system dependent entrainment of the circadian clock; 2) to use these genotype-phenotype relationships as genetic entry points for extending our understanding of these two systems and 3) in order to understand the link between the two systems, to ask how Rhodopsin expression pattern phenotypes affect the circadian entrainment. For the latter part, we will examine circadian behaviours of Rhodopsin-variants under different daylight conditions (colour, intensity, photoperiod, etc.) and in sensitized genetic backgrounds. We also propose to develop statistical methods for detection and quantification of subtle circadian behaviours otherwise undetectable by human eye and for correlating these behaviours with Rhodopsin expression patterns and the underlying genotypes. The project will expand our knowledge of how natural variation shapes the nervous system and the mechanistic implications of this variation for the photoreceptor-circadian clock axis.