The Genetic and Geographical Mosaics of Specialization: A Linkage Map-Based Analysis

University Of Maryland, College Park, College Park MD

Investigators

Abstract

The process of speciation requires the evolution of characters that act as barriers to gene flow. The barriers themselves are well studied but the genetic details of how they evolve and persist remain surprisingly obscure. Recent results from genetic linkage mapping reveal that races of pea aphids specialized on different crop plants differ at relatively few key genomic regions, with much of the genome remaining quite similar between these incipient species. This project concerns whether the same genetic markers linked to genomic regions controlling divergent host plant use in one geographical population of pea aphid (New York) are also associated with divergence between specialized pea aphid races in other locations (Iowa and Maryland). This will be accomplished by genotyping 200 aphids from each location. Finding that the same markers tag divergent genomic regions in different specialist populations will improve our understanding of the genetic processes involved in the evolution of divergent populations and demonstrate the utility of these mapped markers in further analyses of the evolution of specialization and speciation in pea aphids. This project will form the basis of a novel approach to the study of the genetic mechanisms of ecological specialization and speciation. It will also serve as a training ground in multidisciplinary approaches to speciation for undergraduates and graduate students. Moreover, this investigation of the genetics of crop pests will inform and influence future work in agricultural entomology. Both PIs are actively involved in outreach activities designed to further understanding of basic evolutionary principles among agriculturalists, conservation biologists, religious leaders and the general public.