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Vanhoenacker, Eloïse; Sandell, Linnéa; Roze, Denis

<b>Abstract</b><br/>Stabilizing selection around a fixed phenotypic optimum is expected to disfavor sexual reproduction, since asexually reproducing organisms can maintain a higher fitness at equilibrium, while sex disrupts combinations of compensatory mutations. This conclusion rests on the assumption that mutational effects on phenotypic traits are unbiased, that is, mutation does not tend to push phenotypes in any particular direction. In this paper, we consider a model of stabilizing selection acting on an arbitrary number of polygenic traits coded by bialellic loci, and show that mutational bias may greatly reduce the mean fitness of asexual populations compared with sexual ones in regimes where mutations have weak to moderate fitness effects. Indeed, mutation and drift tend to push the population mean phenotype away from the optimum, this effect being enhanced by the low effective population size of asexual populations. In a second part, we present results from individual-based simulations showing that positive rates of sex are favored when mutational bias is present, while the population evolves towards complete asexuality in the absence of bias. We also present analytical (QLE) approximations for the selective forces acting on sex in terms of the effect of sex on the mean and variance in fitness among offspring.; <b>Usage notes</b><br /><div class="o-metadata__file-usage-entry"><h4 class="o-heading__level3-file-title">C++ simulation program</h4><div class="o-metadata__file-description">Program simulating a haploid, facultatively sexual population undergoing stabilizing selection on an arbitrary number of quantitative phenotypic traits, and with genetic variation for the rate of sex.</div><div class="o-metadata__file-name">program.tar</br></div><div class="o-metadata__file-name"></div></div>

Dataset

2020-06-24

This dataset is made available under a Creative Commons CC0 license with the following additional/modified terms and conditions: CC0 Waiver

https://doi.org/10.5683/SP2/FLGBAR

https://creativecommons.org/publicdomain/zero/1.0/