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 Bradbury, Paul Bentzen, Corey J. Morris, Agata T. Gondek-Wyrozemska, Helle Tessand Baalsrud, Marine Servane Ono Brieuc, Olav Sigurd Kjesbu, Jane Aanestad Godiksen, Julia M. I. Barth, Michael Matschiner, Nils Chr. Stenseth, Kjetill S. Jakobsen, Sissel Jentoft, Bastiaan Star
Abstract
) 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.