title: The Role of Recombination in Evolutionary Rescue.
abstract: How likely is it that a population escapes extinction through adaptive evolution? The answer to this question is of great relevance in conservation biology, where we aim at species' rescue and the maintenance of biodiversity, and in agriculture and medicine, where we seek to hamper the emergence of pesticide or drug resistance. By reshuffling the genome, recombination has two antagonistic effects on the probability of evolutionary rescue: it generates and it breaks up favorable gene combinations. Which of the two effects prevails depends on the fitness effects of mutations and on the impact of stochasticity on the allele frequencies. In this article, we analyze a mathematical model for rescue after a sudden environmental change when adaptation is contingent on mutations at two loci. The analysis reveals a complex nonlinear dependence of population survival on recombination. We moreover find that, counterintuitively, a fast eradication of the wild type can promote rescue in the presence of recombination. The model also shows that two-step rescue is not unlikely to happen and can even be more likely than single-step rescue (where adaptation relies on a single mutation), depending on the circumstances.
authors.affiliation: Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria Hildegard.Uecker@env.ethz.ch.
authors.forename: Hildegard
authors.initials: H
authors.lastname: Uecker
authors.affiliation: Mathematics and Biosciences Group, Faculty of Mathematics and Max F. Perutz Laboratories, University of Vienna, 1090 Vienna, Austria.
authors.forename: Joachim
authors.initials: J
authors.lastname: Hermisson
mesh_terms: D000465:Algorithms; D004777:Environment; D004843:Epistasis, Genetic; D019143:Evolution, Molecular; D059647:Gene-Environment Interaction; D005804:Genes, Lethal; D056084:Genetic Fitness; D056426:Genetic Loci; D005828:Genetics, Population; D008957:Models, Genetic; D009154:Mutation; D011995:Recombination, Genetic
keywords: drift; ecology; epistasis; population dynamics; rapid adaptation