DISSERTATION RESEARCH: Divergent selection and the evolution of reproductive isolation across the genus Cakile (Brassicaceae)

Duke University, Durham NC

Investigators

Abstract

Species are defined by their inability to reproduce successfully with other species. Darwin originally argued that new species arose as a consequence of distinct populations adapting to different environments. Despite the widespread acknowledgment that natural selection plays a role in the formation of new species, the question of whether adaptation to different versus similar environments accelerates the evolution of reproductive isolation remains controversial. This study addresses the role of divergent adaptation in speciation by characterizing the degree to which reproductive isolation correlates with adaptive divergence across the genus Cakile, a coastal dune plant that spans a range of environmental variation and geographical isolation throughout Eastern North America, the Caribbean, and the Mediterranean. In addition to addressing long-standing questions concerning the role of the environment and local adaptation in speciation, this research is relevant to conservation initiatives, since Cakile is endemic to the threatened coastal habitat. The project will share information with local and national conservation groups in the Gulf Coast and Caribbean region. The project also has an international component. Undergraduate students will acquire training in experimental design and analysis. Each student will be given the opportunity to develop a component of the project independently. In addition, minority high school students will be recruited to participate in the research during the summers.