Genetic Basis of Natural Variation in C. elegans Chemosensory Behavior

All animals rely on their ability to sense and respond to their constantly changing environments to survive. Because they do not have eyes or ears, C. elegans (small roundworms) depend heavily upon their ability to taste and smell chemical information in their soil environment to find food and avoid danger; animals must move towards chemicals that indicate a food source while avoiding chemicals that indicate potentially harmful environments. Although these senses are key to the survival of animals in the wild, little is known about how naturally occurring genetic diversity affects chemosensory responses, or how adaptive forces might shape the response profiles of animal populations worldwide. Using C. elegans as a model, this project will dissect the mechanisms by which genotype and environment influence how animals interact with their surroundings; the findings will benefit researchers working in organisms ranging from invertebrates to humans. In particular, understanding the naturally occurring range of nociceptive sensitivity could provide new ways to manage aversion and pain across species. Graduate students and undergraduates, will participate in these studies in the lab of the PI. A summer research experience for undergraduates will provide opportunity for independent research and professional development. Funds from this grant will also support a summer stipend for undergraduates from a Liberal Arts College that does not itself have undergraduate research. A fundamental goal of neuroscience is to understand how genes and the environment come together to shape animal behavior, as it is a crucial evolutionary determinant of survival. However, in the case of chemosensation, much of what is known comes from the study of laboratory strains of animals. While these approaches have led to foundational discoveries, they are limited in their ability to couple behavioral variation between individuals of the same species to habitat and evolutionary history. For C. elegans, the isogenic laboratory strain named N2 has been used for chemosensory experiments for over 60 years. ~400 wild isolate strains have recently become available through the Caenorhabditis Natural Diversity Resource (CaeNDR), along with whole-genome sequence data and habitat isolation information, making genome-wide association (GWA) studies now possible. We will use this set of CaeNDR strains and tools to examine natural variation in attractive and aversive chemosensory behaviors between geographically and/or genetically distinct populations of C. elegans. The ability to combine the accumulated knowledge of chemosensory mechanisms in the N2 strain with that of the recently available wild isolate strains positions C. elegans as an ideal system in which to dissect the mechanisms by which genotype and environment influence how animals interact with their surroundings. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.