title: Generation of a neutral FST baseline for testing local adaptation on gill raker number within and between European whitefish ecotypes in the Baltic Sea basin.
abstract: Divergent selection at ecologically important traits is thought to be a major factor driving phenotypic differentiation between populations. To elucidate the role of different evolutionary processes shaping the variation in gill raker number of European whitefish (Coregonus lavaretus sensu lato) in the Baltic Sea basin, we assessed the relationships between genetic and phenotypic variation among and within three whitefish ecotypes (sea spawners, river spawners and lake spawners). To generate expected neutral distribution of FST and to evaluate whether highly variable microsatellite loci resulted in deflated FST estimates compared to less variable markers, we performed population genetic simulations under finite island and hierarchical island models. The genetic divergence observed among (FCT = 0.010) and within (FST = 0.014-0.041) ecotypes was rather low. The divergence in gill raker number, however, was substantially higher between sea and river spawners compared to observed microsatellite data and simulated neutral baseline (PCT > FCT ). This suggests that the differences in gill raker number between sea and river spawners are likely driven by divergent natural selection. We also found strong support for divergent selection on gill raker number among different populations of sea spawners (PST > FST ), most likely caused by highly variable habitat use and diverse diet. The putative role of divergent selection within lake spawners initially inferred from empirical microsatellite data was not supported by simulated FST distributions. This work provides a first formal test of divergent selection on gill raker number in Baltic whitefish, and demonstrates the usefulness of population genetic simulations to generate informative neutral baselines for PST -FST analyses helping to disentangle the effects of stochastic evolutionary processes from natural selection.
authors: Department of Biology, University of Turku, Turku, Finland.
authors: M Y
authors: MY
authors: Ozerov
authors: Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
authors: M
authors: M
authors: Himberg
authors: Department of Biology, University of Turku, Turku, Finland.
authors: T
authors: T
authors: Aykanat
authors: State Research Institute on Lake and River Fisheries (GosNIORKh), St. Petersburg, Russia.
authors: D S
authors: DS
authors: Sendek
authors: Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
authors: H
authors: H
authors: Hägerstrand
authors: Estonian Marine Institute, University of Tartu, Tartu, Estonia.
authors: A
authors: A
authors: Verliin
authors: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia.
authors: T
authors: T
authors: Krause
authors: Department of Aquatic Resources, Institute for Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden.
authors: J
authors: J
authors: Olsson
authors: Department of Biology, University of Turku, Turku, Finland.
authors: C R
authors: CR
authors: Primmer
authors: Department of Biology, University of Turku, Turku, Finland.|Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia.
authors: A
authors: A
authors: Vasemägi
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001454:Baltic States; D005399:Fishes / Q000235:genetics / Q000502:physiology*; D014644:Genetic Variation; D005838:Genotype; D005880:Gills; D018895:Microsatellite Repeats / Q000235:genetics
keywords: Baltic Sea; European whitefish; FST; PST; QST; divergent selection; gill raker number; microsatellites; population genetic simulation