DOI: 10.5061/dryad.p2ngf1w0n
title: Data from: FST and genetic diversity in an island model with background selection

description: Background selection, by which selection on deleterious alleles reduces
 diversity at linked neutral sites, influences patterns of total neutral
 diversity, πT, and genetic differentiation, FST, in structured
 populations. The theory of background selection may be split into two
 regimes: the background selection regime, where selection pressures are
 strong and mutation rates are sufficiently low such that deleterious
 alleles are at a deterministic mutation-selection balance, and the
 interference selection regime, where selection pressures are weak and
 mutation rates are sufficiently high that deleterious alleles accumulate
 and interfere with another, leading to selective interference. Previous
 work has quantified the effects of background selection on πT and FST only
 for deleterious alleles in the background selection regime. Furthermore,
 there is evidence to suggest that migration reduces the effects of
 background selection on FST, but this has not been fully explained. Here,
 we derive novel theory to predict the effects of migration on background
 selection experienced by a subpopulation and extend previous theory from
 the interference selection regime to make predictions in an island model.
 Using simulations, we show that this theory best predicts FST and πT.
 Moreover, we demonstrate that background selection may generate minimal
 increases in FST under sufficiently high migration rates, because
 migration reduces correlated effects on fitness over generations within
 subpopulations. However, we show that background selection may still cause
 substantial reductions in πT, particularly for metapopulations with a
 larger effective population size. Our work further extends the theory of
 background selection into structured populations, and suggests that
 background selection will minimally confound locus-to-locus FST scans.
description: # Data from: FST and genetic diversity in an island model with background
 selection
 [https://doi.org/10.5061/dryad.p2ngf1w0n](https://doi.org/10.5061/dryad.p2ngf1w0n) ## Description of the data and file structure This data was collected by running simulations in SLiM v3.7.1. The relevant code for the simulations, alongside their subsequent analysis and plotting may be found at [https://github.com/asadrh8/FST-BGS](https://github.com/asadrh8/FST-BGS) ### Files and variables To test background selection theory, we ran simulations of panmictic and structured populations. All data files labelled "pi_N" refer to panmictic populations, where the population size is described following an underscore, and all data files labelled "pi_FST" contain data from simulations of an island model (a form of structured population). The label "r" refers to the per base-pair recombination rate in the simulations from which the data is derived, "cM" refers to the map length in centimorgans of the simulated genome, and "M" refers to the map length in morgans (100 cM = 1 M). The "25N" signifies the number of generations the simulations were run for. "mLow", "mInt", and "mHigh" refer to the qualitative amount of migration in the simulations (m = {0.00045, 0.009, 0.09}). **pi_N variables** For the data files pertaining to simulations of a panmictic population, we simply recorded *t* and π. **pi_FST variables** * t: the heterozygous selection coefficient * π_s: the subpopulation genetic diversity * π_t:  the total population genetic diversity * FST: a metric of genetic differentiation Genetic diversity is measured in terms of the average fraction of sites between any two randomly sampled haplotypes that differ.