title: Contemporary isolation-by-distance, but not isolation-by-time, among demes of European Grayling (Thymallus thymallus, Linnaeus) with recent common ancestors.
abstract: The development of isolation by distance (IBD) and isolation by time (IBT) was contrasted among demes of European grayling (Thymallus thymallus) that have diverged within the last 25 generations following colonization of a lake (Lesjaskogsvatnet). We find low but significant levels of genetic differentiation among spawning tributaries and a pattern of IBD among them. We do not, however, find evidence for IBT despite an up to four-week difference in spawning date between "warm/early" and "cold/late" spawning demes and differences in the incubation temperatures experienced by offspring. It appears that IBD has developed more rapidly than IBT in this system and that adaptive divergence has been initiated in the absence of IBT. Although analysis of selected loci could reveal reduced recombination in parts of the genome associated with temporal divergence, our analysis of neutral genetic data suggests that IBD is a more important isolating mechanism in the early stages of adaptive divergence in European grayling.
authors.affiliation: Centre for Ecological and Evolutionary Synthesis, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo, Norway
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Barson
authors.forename: Thrond O
authors.initials: TO
authors.lastname: Haugen
authors.forename: L Asbjørn
authors.initials: LA
authors.lastname: Vøllestad
authors.forename: Craig R
authors.initials: CR
authors.lastname: Primmer
mesh_terms: D000818:Animals; D005618:Fresh Water; D014644:Genetic Variation; D009664:Norway; D012487:Salmonidae / Q000235:genetics* / Q000254:growth & development / Q000502:physiology