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The two‐fold cost of sex: Experimental evidence from a natural system

Over four decades ago, John Maynard Smith showed that a mutation causing asexual reproduction should rapidly spread in a dioecious sexual population. His reasoning was that the per‐capita birth rate of an asexual population would exceed that of a sexual population, because asexual females do not inv...

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Autores principales: Gibson, Amanda K., Delph, Lynda F., Lively, Curtis M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089407/
https://www.ncbi.nlm.nih.gov/pubmed/30233811
http://dx.doi.org/10.1002/evl3.1
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author Gibson, Amanda K.
Delph, Lynda F.
Lively, Curtis M.
author_facet Gibson, Amanda K.
Delph, Lynda F.
Lively, Curtis M.
author_sort Gibson, Amanda K.
collection PubMed
description Over four decades ago, John Maynard Smith showed that a mutation causing asexual reproduction should rapidly spread in a dioecious sexual population. His reasoning was that the per‐capita birth rate of an asexual population would exceed that of a sexual population, because asexual females do not invest in sons. Hence, there is a cost of sexual reproduction that Maynard Smith called the “cost of males.” Assuming all else is otherwise equal among sexual and asexual females, the cost is expected to be two‐fold in outcrossing populations with separate sexes and equal sex ratios. Maynard Smith's model led to one of the most interesting questions in evolutionary biology: why is there sex? There are, however, no direct estimates of the proposed cost of sex. Here, we measured the increase in frequency of asexual snails in natural, mixed population of sexual and asexual snails in large outdoor mesocosms. We then extended Maynard Smith's model to predict the change in frequency of asexuals for any cost of sex and for any initial frequency of asexuals. Consistent with the “all‐else equal” assumption, we found that the increase in frequency of asexual snails closely matched that predicted under a two‐fold cost.
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spelling pubmed-60894072018-09-17 The two‐fold cost of sex: Experimental evidence from a natural system Gibson, Amanda K. Delph, Lynda F. Lively, Curtis M. Evol Lett Letters Over four decades ago, John Maynard Smith showed that a mutation causing asexual reproduction should rapidly spread in a dioecious sexual population. His reasoning was that the per‐capita birth rate of an asexual population would exceed that of a sexual population, because asexual females do not invest in sons. Hence, there is a cost of sexual reproduction that Maynard Smith called the “cost of males.” Assuming all else is otherwise equal among sexual and asexual females, the cost is expected to be two‐fold in outcrossing populations with separate sexes and equal sex ratios. Maynard Smith's model led to one of the most interesting questions in evolutionary biology: why is there sex? There are, however, no direct estimates of the proposed cost of sex. Here, we measured the increase in frequency of asexual snails in natural, mixed population of sexual and asexual snails in large outdoor mesocosms. We then extended Maynard Smith's model to predict the change in frequency of asexuals for any cost of sex and for any initial frequency of asexuals. Consistent with the “all‐else equal” assumption, we found that the increase in frequency of asexual snails closely matched that predicted under a two‐fold cost. John Wiley and Sons Inc. 2017-05-03 /pmc/articles/PMC6089407/ /pubmed/30233811 http://dx.doi.org/10.1002/evl3.1 Text en © 2017 The Author(s). Evolution Letters published by Wiley Periodicals, Inc. on behalf of Society for the Study of Evolution (SSE) and European Society for Evolutionary Biology (ESEB). This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Letters
Gibson, Amanda K.
Delph, Lynda F.
Lively, Curtis M.
The two‐fold cost of sex: Experimental evidence from a natural system
title The two‐fold cost of sex: Experimental evidence from a natural system
title_full The two‐fold cost of sex: Experimental evidence from a natural system
title_fullStr The two‐fold cost of sex: Experimental evidence from a natural system
title_full_unstemmed The two‐fold cost of sex: Experimental evidence from a natural system
title_short The two‐fold cost of sex: Experimental evidence from a natural system
title_sort two‐fold cost of sex: experimental evidence from a natural system
topic Letters
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089407/
https://www.ncbi.nlm.nih.gov/pubmed/30233811
http://dx.doi.org/10.1002/evl3.1
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