title: Genetic architecture of age at maturity can generate divergent and disruptive harvest-induced evolution.
abstract: Life-history traits are generally assumed to be inherited quantitatively. Fishing that targets large, old individuals is expected to decrease age at maturity. In Atlantic salmon (Salmo salar), it has recently been discovered that sea age at maturity is under strong control by a single locus with sexually dimorphic expression of heterozygotes, which makes it less intuitive to predict how life histories respond to selective fishing. We explore evolutionary responses to fishing in Atlantic salmon, using eco-evolutionary simulations with two alternative scenarios for the genetic architecture of age at maturity: (i) control by multiple loci with additive effects and (ii) control by one locus with sexually dimorphic expression. We show that multi-locus control leads to unidirectional evolution towards earlier maturation, whereas single-locus control causes largely divergent and disruptive evolution of age at maturity without a clear phenotypic trend but a wide range of alternative evolutionary trajectories and greater trait variability within trajectories. Our results indicate that the range of evolutionary responses to selective fishing can be wider than previously thought and that a lack of phenotypic trend need not imply that evolution has not occurred. These findings underscore the role of genetic architecture of life-history traits in understanding how human-induced selection can shape target populations.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.
authors.affiliation: Department of Environmental Sciences, University of Helsinki, PO Box 65, 00014 Helsinki, Finland anna.kuparinen@helsinki.fi.
authors.forename: Anna
authors.identifier: 0000-0002-7807-8946
authors.initials: A
authors.lastname: Kuparinen
authors.affiliation: Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2.|Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway.|Department of Natural Sciences, University of Agder, PO Box 422, 4604 Kristiansand, Norway.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hutchings
mesh_terms: D000375:Aging / Q000235:genetics*; D000818:Animals; D005075:Biological Evolution; D005260:Female; D005398:Fisheries; D008297:Male; D008957:Models, Genetic; D010641:Phenotype; D020317:Salmo salar / Q000235:genetics / Q000502:physiology*; D012641:Selection, Genetic
keywords: Atlantic salmon; Salmo salar; Vgll3TOP; age at maturation; dimorphism; fisheries-induced evolution