Data from: 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

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-, river 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.

Ozerov_et_al_2015_Whitefish_PST-FSTGill-raker number and microsatellite
genotypesOzerov_et_al_2015_WF_PST_FST_Dryad.xlsx