(1) Instituto de Física, Universidade Federal Fluminense, Av. Litoranea, s/n, Boa Viagem, Niterói, 24210-340, RJ, Brazil;(2) Institute for Computer Physics, University of Stuttgart, Pfaffenwaldring 27, 70569 Stuttgart, Germany
Abstract:
Parapatric speciation is studied using an individual-based model with sexual
reproduction. We combine the theory of mutation accumulation for biological ageing
with an environmental selection pressure that varies according to the individuals
geographical positions and phenotypic traits. Fluctuations and genetic diversity of
large populations are crucial ingredients to model the features of evolutionary
branching and are intrinsic properties of the model.
Its implementation on a spatial lattice gives interesting insights into the population
dynamics of speciation on a geographical landscape and the disruptive selection that leads
to the divergence of phenotypes.
Our results suggest that assortative mating is not an obligatory ingredient to obtain
speciation in large populations at low gene flow.