Genomic stability through time despite decades of exploitation in cod on both sides of the Atlantic

Malin L Pinsky; Anne Maria Eikeset; Cecilia Helmerson; Ian R Bradbury; Paul Bentzen; Corey Morris; Agata T Gondek-Wyrozemska; Helle Tessand Baalsrud; Marine Servane Ono Brieuc; Olav Sigurd Kjesbu; Jane A Godiksen; Julia M I Barth; Michael Matschiner; Nils Chr Stenseth; Kjetill S Jakobsen; Sissel Jentoft; Bastiaan Star

doi:10.1073/pnas.2025453118

Genomic stability through time despite decades of exploitation in cod on both sides of the Atlantic

Proc Natl Acad Sci U S A. 2021 Apr 13;118(15):e2025453118. doi: 10.1073/pnas.2025453118.

Authors

Malin L Pinsky¹, Anne Maria Eikeset², Cecilia Helmerson², Ian R Bradbury³, Paul Bentzen⁴, Corey Morris³, Agata T Gondek-Wyrozemska², Helle Tessand Baalsrud², Marine Servane Ono Brieuc², Olav Sigurd Kjesbu⁵, Jane A Godiksen⁶, Julia M I Barth^{2

7}, Michael Matschiner^{2

8

9}, Nils Chr Stenseth^{10

11}, Kjetill S Jakobsen², Sissel Jentoft², Bastiaan Star¹⁰

Affiliations

¹ Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ 08540; malin.pinsky@rutgers.edu n.c.stenseth@mn.uio.no bastiaan.star@ibv.uio.no.
² Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Blindern, NO-0316 Oslo, Norway.
³ Science Branch, Fisheries and Oceans Canada, St. John's, NL A1C 5X1, Canada.
⁴ Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
⁵ Marine Ecosystems and Resources, Institute of Marine Research, NO-5817 Bergen, Norway.
⁶ Demersal Fish, Institute of Marine Research, NO-5817 Bergen, Norway.
⁷ Zoological Institute, Department of Environmental Sciences, University of Basel, 4051 Basel, Switzerland.
⁸ Department of Palaeontology, University of Zurich, 8006 Zurich, Switzerland.
⁹ Palaeontological Museum, University of Zurich, 8006 Zurich, Switzerland.
¹⁰ Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Blindern, NO-0316 Oslo, Norway; malin.pinsky@rutgers.edu n.c.stenseth@mn.uio.no bastiaan.star@ibv.uio.no.
¹¹ Centre of Coastal Research, University of Agder, NO-4604 Kristiansand, Norway.

Abstract

The mode and extent of rapid evolution and genomic change in response to human harvesting are key conservation issues. Although experiments and models have shown a high potential for both genetic and phenotypic change in response to fishing, empirical examples of genetic responses in wild populations are rare. Here, we compare whole-genome sequence data of Atlantic cod (Gadus morhua) that were collected before (early 20th century) and after (early 21st century) periods of intensive exploitation and rapid decline in the age of maturation from two geographically distinct populations in Newfoundland, Canada, and the northeast Arctic, Norway. Our temporal, genome-wide analyses of 346,290 loci show no substantial loss of genetic diversity and high effective population sizes. Moreover, we do not find distinct signals of strong selective sweeps anywhere in the genome, although we cannot rule out the possibility of highly polygenic evolution. Our observations suggest that phenotypic change in these populations is not constrained by irreversible loss of genomic variation and thus imply that former traits could be reestablished with demographic recovery.

Keywords: fisheries-induced evolution; genetic diversity; historical DNA; population genomics; selective sweeps.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Atlantic Ocean
Biomass*
Evolution, Molecular
Gadus morhua / genetics*
Gadus morhua / physiology
Genomic Instability*
Polymorphism, Genetic*