title: Genetically distinct populations of northern shrimp, Pandalus borealis, in the North Atlantic: adaptation to different temperatures as an isolation factor.
abstract: The large-scale population genetic structure of northern shrimp, Pandalus borealis, was investigated over the species' range in the North Atlantic, identifying multiple genetically distinct groups. Genetic divergence among sample localities varied among 10 microsatellite loci (range: FST = -0.0002 to 0.0475) with a highly significant average (FST = 0.0149; P < 0.0001). In contrast, little or no genetic differences were observed among temporal replicates from the same localities (FST = 0.0004; P = 0.33). Spatial genetic patterns were compared to geographic distances, patterns of larval drift obtained through oceanographic modelling, and temperature differences, within a multiple linear regression framework. The best-fit model included all three factors and explained approximately 29% of all spatial genetic divergence. However, geographic distance and larval drift alone had only minor effects (2.5-4.7%) on large-scale genetic differentiation patterns, whereas bottom temperature differences explained most (26%). Larval drift was found to promote genetic homogeneity in parts of the study area with strong currents, but appeared ineffective across large temperature gradients. These findings highlight the breakdown of gene flow in a species with a long pelagic larval phase (up to 3 months) and indicate a role for local adaptation to temperature conditions in promoting evolutionary diversification and speciation in the marine environment.
authors.affiliation: Department of Biosciences, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo, P.O. Box 1066 Blindern, N-0316, Oslo, Norway.
authors.forename: Per Erik
authors.initials: PE
authors.lastname: Jorde
authors.forename: Guldborg
authors.initials: G
authors.lastname: Søvik
authors.forename: Jon-Ivar
authors.initials: JI
authors.lastname: Westgaard
authors.forename: Jon
authors.initials: J
authors.lastname: Albretsen
authors.forename: Carl
authors.initials: C
authors.lastname: André
authors.forename: Carsten
authors.initials: C
authors.lastname: Hvingel
authors.forename: Torild
authors.initials: T
authors.lastname: Johansen
authors.forename: Anne Dagrun
authors.initials: AD
authors.lastname: Sandvik
authors.forename: Michael
authors.initials: M
authors.lastname: Kingsley
authors.forename: Knut Eirik
authors.initials: KE
authors.lastname: Jørstad
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D063147:Animal Distribution; D000818:Animals; D001267:Atlantic Ocean; D051456:Gene Flow; D005828:Genetics, Population; D018895:Microsatellite Repeats; D008957:Models, Genetic; D015233:Models, Statistical; D033542:Pandalidae / Q000145:classification*; D013696:Temperature
keywords: adaptation; gene flow; marine genetic structure; oceanographic modelling; pelagic larval duration; temperature