Can tight linkage mimic pleiotropy during speciation? The effects and evolution of recombination between mating and local-adaptation loci.

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

This research will develop mathematical models that examine the evolutionary processes by which one species splits into two: speciation. It has been thought that the genes that are uniquely important in promoting speciation are those that have dual functions that both allow the survival of individuals in their environment and allow individuals to attract mates of the same species. However, such genes appear to be quite rare. Some evidence exists that close physical proximity on a chromosome of genes involved in these two functions (survival and mate attraction) may also be very effective in allowing populations of recently diverged species that then come in contact to maintain their identity. The research will further explore the conditions under which close proximity of these genes mimics the properties of one gene with two functions, both in the maintenance of species and in the generation of new species. The researchers will also develop and distribute curriculum materials for teaching biology majors how to approach questions using mathematical modeling. The project will address these questions through mathematical modeling using a combination of population-genetic and individual-based approaches. These models will first address whether tight linkage of genes under ecologically divergent selection and genes that are the targets of assortative mating can mimic a single pleiotropic gene with these functions, concentrating on the evolution of choosiness during assortative mating. Next, the researchers will address whether traits under divergent selection and those used in mate choice will evolve to co-localize during the process of speciation with gene flow. This will be explored both by assessing the evolution of modifiers of recombination rate and by examining the fate of standing variation of genes when ecological and mating traits are controlled by many loci across the genome. 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.