title: The genetics of speciation: Insights from Fisher's geometric model.
abstract: Research in speciation genetics has uncovered many robust patterns in intrinsic reproductive isolation, and fitness landscape models have been useful in interpreting these patterns. Here, we examine fitness landscapes based on Fisher's geometric model. Such landscapes are analogous to models of optimizing selection acting on quantitative traits, and have been widely used to study adaptation and the distribution of mutational effects. We show that, with a few modifications, Fisher's model can generate all of the major findings of introgression studies (including "speciation genes" with strong deleterious effects, complex epistasis and asymmetry), and the major patterns in overall hybrid fitnesses (including Haldane's Rule, the speciation clock, heterosis, hybrid breakdown, and male-female asymmetry in the F1). We compare our approach to alternative modeling frameworks that assign fitnesses to genotypes by identifying combinations of incompatible alleles. In some cases, the predictions are importantly different. For example, Fisher's model can explain conflicting empirical results about the rate at which incompatibilities accumulate with genetic divergence. In other cases, the predictions are identical. For example, the quality of reproductive isolation is little affected by the manner in which populations diverge.
authors.affiliation: Université Montpellier, Institut des Sciences de l'Évolution, UMR 5554, Montpellier Cedex 05, France.|CNRS, Institut des Sciences de l'Évolution, UMR 5554, OREME Station Marine, Sète, France.|Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom.
authors.forename: Christelle
authors.initials: C
authors.lastname: Fraïsse
authors.affiliation: Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom.
authors.forename: P Alexander
authors.initials: PA
authors.lastname: Gunnarsson
authors.affiliation: CNRS, UMI 3614, Evolutionary Biology and Ecology of Algae, Roscoff, France.|Sorbonne Universités, UPMC University Paris VI, Roscoff, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Roze
authors.affiliation: Université Montpellier, Institut des Sciences de l'Évolution, UMR 5554, Montpellier Cedex 05, France.|CNRS, Institut des Sciences de l'Évolution, UMR 5554, OREME Station Marine, Sète, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bierne
authors.affiliation: Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom. j.j.welch@gen.cam.ac.uk.
authors.forename: John J
authors.initials: JJ
authors.lastname: Welch
mesh_terms: D049810:Genetic Speciation; D008957:Models, Genetic; D060047:Reproductive Isolation
keywords: Dobzhansky-Muller incompatibilities; hybridization; reproductive isolation; snowball effect