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Mutational robustness changes during long-term adaptation in laboratory budding yeast populations

As an adapting population traverses the fitness landscape, its local neighborhood (i.e., the collection of fitness effects of single-step mutations) can change shape because of interactions with mutations acquired during evolution. These changes to the distribution of fitness effects can affect both...

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Autores principales: Johnson, Milo S, Desai, Michael M
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9355567/
https://www.ncbi.nlm.nih.gov/pubmed/35880743
http://dx.doi.org/10.7554/eLife.76491
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author Johnson, Milo S
Desai, Michael M
author_facet Johnson, Milo S
Desai, Michael M
author_sort Johnson, Milo S
collection PubMed
description As an adapting population traverses the fitness landscape, its local neighborhood (i.e., the collection of fitness effects of single-step mutations) can change shape because of interactions with mutations acquired during evolution. These changes to the distribution of fitness effects can affect both the rate of adaptation and the accumulation of deleterious mutations. However, while numerous models of fitness landscapes have been proposed in the literature, empirical data on how this distribution changes during evolution remains limited. In this study, we directly measure how the fitness landscape neighborhood changes during laboratory adaptation. Using a barcode-based mutagenesis system, we measure the fitness effects of 91 specific gene disruption mutations in genetic backgrounds spanning 8000–10,000 generations of evolution in two constant environments. We find that the mean of the distribution of fitness effects decreases in one environment, indicating a reduction in mutational robustness, but does not change in the other. We show that these distribution-level patterns result from differences in the relative frequency of certain patterns of epistasis at the level of individual mutations, including fitness-correlated and idiosyncratic epistasis.
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spelling pubmed-93555672022-08-06 Mutational robustness changes during long-term adaptation in laboratory budding yeast populations Johnson, Milo S Desai, Michael M eLife Evolutionary Biology As an adapting population traverses the fitness landscape, its local neighborhood (i.e., the collection of fitness effects of single-step mutations) can change shape because of interactions with mutations acquired during evolution. These changes to the distribution of fitness effects can affect both the rate of adaptation and the accumulation of deleterious mutations. However, while numerous models of fitness landscapes have been proposed in the literature, empirical data on how this distribution changes during evolution remains limited. In this study, we directly measure how the fitness landscape neighborhood changes during laboratory adaptation. Using a barcode-based mutagenesis system, we measure the fitness effects of 91 specific gene disruption mutations in genetic backgrounds spanning 8000–10,000 generations of evolution in two constant environments. We find that the mean of the distribution of fitness effects decreases in one environment, indicating a reduction in mutational robustness, but does not change in the other. We show that these distribution-level patterns result from differences in the relative frequency of certain patterns of epistasis at the level of individual mutations, including fitness-correlated and idiosyncratic epistasis. eLife Sciences Publications, Ltd 2022-07-26 /pmc/articles/PMC9355567/ /pubmed/35880743 http://dx.doi.org/10.7554/eLife.76491 Text en © 2022, Johnson and Desai https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Evolutionary Biology
Johnson, Milo S
Desai, Michael M
Mutational robustness changes during long-term adaptation in laboratory budding yeast populations
title Mutational robustness changes during long-term adaptation in laboratory budding yeast populations
title_full Mutational robustness changes during long-term adaptation in laboratory budding yeast populations
title_fullStr Mutational robustness changes during long-term adaptation in laboratory budding yeast populations
title_full_unstemmed Mutational robustness changes during long-term adaptation in laboratory budding yeast populations
title_short Mutational robustness changes during long-term adaptation in laboratory budding yeast populations
title_sort mutational robustness changes during long-term adaptation in laboratory budding yeast populations
topic Evolutionary Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9355567/
https://www.ncbi.nlm.nih.gov/pubmed/35880743
http://dx.doi.org/10.7554/eLife.76491
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