Identification of the genetic and phenotypic basis of adaptation to new food sources in two laboratory domesticated Caenorhabditis elegans strains

The ability to obtain energy from natural environments is of fundamental importance to an animal’s survival and depends on both finding food and metabolizing it into a useful molecular source of energy. As organisms encounter new environments, feeding strategies and metabolic networks can be out of balance with new potential dietary sources, creating evolutionary pressure for animals to adapt. In my doctoral thesis, I studied how two laboratory strains of C. elegans, N2 and LSJ2, adapted to new food sources. The first chapter reviews current genetic approach to study adaptive mutations and genetic basis of complex traits. The second chapter describes the finding that how the pleiotropic traits of two derived alleles of neural genes npr-1 and glb-5 in N2 regulate fitness effects to adapt to the new food source. The third chapter describes the finding that identification of a beneficial de novo complex genomic rearrangements at rcan-1 gene, an ortholog of human Down Syndrome correlated gene RCAN1/DSCR1. This complex rearrangement provides animal another strategy to adapt to the new food source. The fourth chapter describes the work to identify the adaptive alleles and their fitness effects under different environments including three different feeding conditions, two different temperatures, and the growth condition with anthelmintic drugs. The last chapter summarizes and discusses all the findings. My doctoral thesis research demonstrates that laboratory evolution can serve as a powerful tool to study the genetic and phenotypic basis that regulate fitness in metazoan.Ph.D