Spatially distributed population dynamics and speciation processes

Abstract

Evolutionary processes can lead to significant changes in the characteristics of a species, including its ramification into reproductively isolated species. Although it is possible to study these processes considering a single initial species subjected to external influences, it is desirable to take into account interactions among species, that may naturally include mechanisms of naturalselection and lead to the coevolution of the system. In this proposal we intend to develop theoretical and simulation models in population dynamics that can describe the genetic, ecological and geographical components of a single population or two populations interacting via predation or mutualism. The important characteristics of these models are sexual reproduction and theindividual based treatment. In the case of a single species we want to further study the problem of ring species, where there is partial geographic isolation, and model the speciation of the cichlid fish in African lakes, which underwent recent and rapid speciation. One of the goals with this study is to understand the role of expanding fronts in processes of colonization, with or without barriers. Coevolution will be initially studies with a predatorr-prey system without spatial barriers. The prey genome will play a role in sexualreproduction and will also code for a venom that protects the prey against predator attacks. The predator genome, on the other hand, codes for a resistance to the venom, creating an arms race. We want to understand the role of selection, included in the balance between venom and resistance, affects the stability of the populations and the processes of speciation in both species.The new ingredient here is the treatment of the genetic evolution with sexual reproduction, which is very different from the cloning mechanism usually applied to viruses. From the theoretical point of view we will generalize our previous results on the evolution of allelic frequencies to more than two genes. (AU)