Understanding the process of how new species form (speciation) is central to modern biology. Species are most commonly identified as groups of animals that are reproductively isolated from other such groups. This collaborative project will use two swallowtail butterfly species, Papilio glaucus and P. canadensis, and a discrete zone where hybrids of these two species can be found (a hybrid zone), as a model system to study the genetic basis of reproductive isolation. These two species differ in several ecologically important traits that are linked to their sex chromosomes, yet are still partly capable of forming fertile hybrids. These features allow study of the genetics of reproductive isolation between these species in the context of these ecological differences. The research will produce a genetic map of the Papilio X-chromosome and will identify regions of the X-chromosome that are linked to ecologically important traits. The degree to which natural selection in the hybrid zone prevents between-species exchanges of genetic material that is closely linked to these traits will be tested.
Papilio swallowtails are a common and easily recognizable butterfly in North America, and will serve as a publicly accessible tool for the study of speciation. This work will significantly contribute to genetic resources for butterfly and moth researchers. Insights gained by the proposed research will be broadly applicable to understanding speciation in a wide variety of plant and animal groups. In addition, publicly available software will be developed and made available to facilitate the study of speciation by other researchers.
