Behavior is known to be influenced by natural genetic variation among individuals, yet the precise physiological mechanisms that alter behavior as a result of this variation are poorly understood. The solution to this problem depends both on identifying genes responsible for natural variation in behavioral responses and on understanding the physiology of how those genes affect neural function. Caenorhabditis elegans, a free-living soil-dwelling nematode, is an ideal organism to address the effects of natural variation on behavior. It has a relatively simple nervous system and a fully annotated sequenced genome, and wild isolates of this species show extremely different temperature preferences. This study will use genetic crosses to map and clone the genes responsible for natural variation in behavior. Microfluidic devices will then be used to create a precise temperature choice environment, allowing the physiological basis of these differences to be analyzed using calcium imaging of individual neurons. This work has broader impacts via interdisciplinary graduate training, involvement of undergraduates in research, and community-oriented scientific education through a Campus Educational Network. This will be among the first studies to identify specific changes in multiple genes that work together to cause variation in the physiological mechanisms of a complex behavior. These connections are necessary to begin to understand the vast diversity of behavioral responses within the natural world, as well as within human populations.
