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Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects
The most consistent result in more than two decades of experimental evolution is that the fitness of populations adapting to a constant environment does not increase indefinitely, but reaches a plateau. Using experimental evolution with bacteriophage, we show here that the converse is also true. In...
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Formato: | Texto |
Lenguaje: | English |
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Public Library of Science
2007
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1845161/ https://www.ncbi.nlm.nih.gov/pubmed/17407380 http://dx.doi.org/10.1371/journal.pbio.0050094 |
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author | Silander, Olin K Tenaillon, Olivier Chao, Lin |
author_facet | Silander, Olin K Tenaillon, Olivier Chao, Lin |
author_sort | Silander, Olin K |
collection | PubMed |
description | The most consistent result in more than two decades of experimental evolution is that the fitness of populations adapting to a constant environment does not increase indefinitely, but reaches a plateau. Using experimental evolution with bacteriophage, we show here that the converse is also true. In populations small enough such that drift overwhelms selection and causes fitness to decrease, fitness declines down to a plateau. We demonstrate theoretically that both of these phenomena must be due either to changes in the ratio of beneficial to deleterious mutations, the size of mutational effects, or both. We use mutation accumulation experiments and molecular data from experimental evolution to show that the most significant change in mutational effects is a drastic increase in the rate of beneficial mutation as fitness decreases. In contrast, the size of mutational effects changes little even as organismal fitness changes over several orders of magnitude. These findings have significant implications for the dynamics of adaptation. |
format | Text |
id | pubmed-1845161 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2007 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-18451612007-05-01 Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects Silander, Olin K Tenaillon, Olivier Chao, Lin PLoS Biol Research Article The most consistent result in more than two decades of experimental evolution is that the fitness of populations adapting to a constant environment does not increase indefinitely, but reaches a plateau. Using experimental evolution with bacteriophage, we show here that the converse is also true. In populations small enough such that drift overwhelms selection and causes fitness to decrease, fitness declines down to a plateau. We demonstrate theoretically that both of these phenomena must be due either to changes in the ratio of beneficial to deleterious mutations, the size of mutational effects, or both. We use mutation accumulation experiments and molecular data from experimental evolution to show that the most significant change in mutational effects is a drastic increase in the rate of beneficial mutation as fitness decreases. In contrast, the size of mutational effects changes little even as organismal fitness changes over several orders of magnitude. These findings have significant implications for the dynamics of adaptation. Public Library of Science 2007-04 2007-04-03 /pmc/articles/PMC1845161/ /pubmed/17407380 http://dx.doi.org/10.1371/journal.pbio.0050094 Text en © 2007 Silander et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Silander, Olin K Tenaillon, Olivier Chao, Lin Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects |
title | Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects |
title_full | Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects |
title_fullStr | Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects |
title_full_unstemmed | Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects |
title_short | Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects |
title_sort | understanding the evolutionary fate of finite populations: the dynamics of mutational effects |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1845161/ https://www.ncbi.nlm.nih.gov/pubmed/17407380 http://dx.doi.org/10.1371/journal.pbio.0050094 |
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