Collaborative Research: Does Cytonuclear Coevolution Drive Reproductive Isolation? Dissecting the Architecture of Genetic Incompatibility Across a Species Range

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

The natural world exhibits a vast array of biodiversity which ensures the stability of ecosystems, the services they provide, and has intrinsic aesthetic value. Individual species are critical elements of this biodiversity and understanding how new species form is key to ensuring maintenance of diversity. Interactions between the nuclear genome and organelle (mitochondria and chloroplast) genomes underlie key processes including respiration and photosynthesis. These interactions are an underappreciated and yet potentially powerful driver of the earliest stages of speciation. The planned research will investigate the contribution of intergenomic interactions to incompatibility between populations of a species. The research will use state-of-the art techniques to identify the genomic basis of incompatibility between the nuclear and organelle genomes and determine the ability of such incompatibility to maintain genetic divergence and facilitate speciation in a contact zone. The project will also introduce undergraduate students and high-school and community college teachers to core ideas about species formation and evolution through hands-on experience with the newest genomic sequencing technologies in a novel course-based lab module and workshop. Finally, the project will provide training at the undergraduate, graduate, and post-graduate level. Interactions between cytoplasmic and nuclear gene products are expected to drive intergenomic coevolution, leading to the potential for genetic incompatibility and reproductive isolation between populations with divergent cytoplasmic genomes. While such cytonuclear incompatibility (CNI) has been posited to be among the earliest reproductive barriers to develop during speciation, our understanding of the dynamics of CNI at the early stages of speciation remains limited, particularly for plastid-driven speciation. The research will examine the dynamics of plastid driven CNI in Campanula americana, creating a powerful set of genomic resources, characterizing variation in the genetic architecture of CNI across lineages, and leveraging a natural contact zone to evaluate whether exposure to selection alters the genetic architecture of CNI relative to allopatry. Together, these data will provide insight into the evolutionary dynamics of plastid-nuclear incompatibility and how these dynamics may drive the early stages of speciation. 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.