Currently, there is not enough good data on what types of genetic changes occur when organisms evolve an adaptation. This data can only come from high-resolution genetic analyses of natural adaptations. The fruitfly, Drosophila sechellia, is uniquely suited for such an analysis as it can be manipulated genetically and has an indisputable adaptation. A close relative of D. melanogaster, a genetic model species, D. sechellia has adapted to consuming the fruit of Morinda citrifolia, a fruit that is toxic to other fruitflies. The first two experiments in this grant are in-depth genetic analyses of D. sechellia's adaptation. The genes involved in this adaptation will be precisely mapped and their effects estimated. This data is a necessary first step towards the identification and cloning of the adaptive alleles. The final experiment will determine the relative importance of standing genetic variation versus new mutations in the evolution of an adaptation by artificially evolving resistance in related species of fruitflies. The proposed research will help us understand how organisms genetically change in response to environmental change. Specifically, this grant will impact our understanding of how insects evolve resistance to plant produced pesticides and will give insight into how insects choose the plants upon which they feed.
