Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation

Abstract Background Evolution of microbes under laboratory selection produces genetically diverse populations, owing to the continuous input of mutations and to competition among lineages. Whole-genome whole-population sequencing makes it possible to identify mutations arising in such populations, t...

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Main Authors: Katja Schwartz, Margie Kinnersley, Charles Ross Lindsey, Gavin Sherlock, Frank Rosenzweig
Format: Article
Language:English
Published: BMC 2025-08-01
Series:BMC Biology
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Online Access:https://doi.org/10.1186/s12915-025-02331-7
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author Katja Schwartz
Margie Kinnersley
Charles Ross Lindsey
Gavin Sherlock
Frank Rosenzweig
author_facet Katja Schwartz
Margie Kinnersley
Charles Ross Lindsey
Gavin Sherlock
Frank Rosenzweig
author_sort Katja Schwartz
collection DOAJ
description Abstract Background Evolution of microbes under laboratory selection produces genetically diverse populations, owing to the continuous input of mutations and to competition among lineages. Whole-genome whole-population sequencing makes it possible to identify mutations arising in such populations, to use them to discern functional modules where adaptation occurs, and then map gene structure–function relationships. Here, we report on the use of this approach, adaptive genetics, to discover targets of selection and the mutational consequences thereof in E. coli evolving under chronic nutrient limitation. Results Replicate bacterial populations were cultured for ≥ 300 generations in glucose limited chemostats and sequenced every 50 generations at 1000X-coverage, enabling identification of mutations that rose to ≥ 1% frequency. Thirty-nine genes qualified as high value targets of selection, being mutated far more often than would be expected by chance. A majority of these encode regulatory proteins that control gene expression at the transcriptional (e.g., RpoS and OmpR), post-transcriptional (e.g., Hfq and ProQ), and post-translational (e.g., GatZ) levels. The downstream effects of these regulatory mutations likely impact not only acquisition and processing of limiting glucose, but also assembly of structural elements such as lipopolysaccharide, periplasmic glucans, and cell surface appendages such as flagella and fimbriae. Whether regulatory or structural in nature, recurrent mutations at high value targets tend to cluster at sites either known or predicted to be involved in RNA–protein or protein–protein interactions. Conclusions Our observations highlight the value of experimental evolution as a proving ground for inferences gathered from traditional molecular genetics. By coupling experimental evolution to whole-genome, whole-population sequencing, adaptive genetics makes it possible not only the genes whose mutation confers a selective advantage, but also to discover which residues in which genes are most likely to confer a particular type of selective advantage and why.
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spelling doaj-art-df8db396dbd54371be14952567d7c2302025-08-24T11:50:24ZengBMCBMC Biology1741-70072025-08-0123113210.1186/s12915-025-02331-7Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitationKatja Schwartz0Margie Kinnersley1Charles Ross Lindsey2Gavin Sherlock3Frank Rosenzweig4Department of Genetics, Stanford University School of MedicineDivision of Biological Sciences, The University of MontanaSchool of Biological Sciences, Georgia Institute of TechnologyDepartment of Genetics, Stanford University School of MedicineDivision of Biological Sciences, The University of MontanaAbstract Background Evolution of microbes under laboratory selection produces genetically diverse populations, owing to the continuous input of mutations and to competition among lineages. Whole-genome whole-population sequencing makes it possible to identify mutations arising in such populations, to use them to discern functional modules where adaptation occurs, and then map gene structure–function relationships. Here, we report on the use of this approach, adaptive genetics, to discover targets of selection and the mutational consequences thereof in E. coli evolving under chronic nutrient limitation. Results Replicate bacterial populations were cultured for ≥ 300 generations in glucose limited chemostats and sequenced every 50 generations at 1000X-coverage, enabling identification of mutations that rose to ≥ 1% frequency. Thirty-nine genes qualified as high value targets of selection, being mutated far more often than would be expected by chance. A majority of these encode regulatory proteins that control gene expression at the transcriptional (e.g., RpoS and OmpR), post-transcriptional (e.g., Hfq and ProQ), and post-translational (e.g., GatZ) levels. The downstream effects of these regulatory mutations likely impact not only acquisition and processing of limiting glucose, but also assembly of structural elements such as lipopolysaccharide, periplasmic glucans, and cell surface appendages such as flagella and fimbriae. Whether regulatory or structural in nature, recurrent mutations at high value targets tend to cluster at sites either known or predicted to be involved in RNA–protein or protein–protein interactions. Conclusions Our observations highlight the value of experimental evolution as a proving ground for inferences gathered from traditional molecular genetics. By coupling experimental evolution to whole-genome, whole-population sequencing, adaptive genetics makes it possible not only the genes whose mutation confers a selective advantage, but also to discover which residues in which genes are most likely to confer a particular type of selective advantage and why.https://doi.org/10.1186/s12915-025-02331-7E. coliExperimental evolutionWhole genome sequencingFunctional genomicsAdaptive geneticsParallelism
spellingShingle Katja Schwartz
Margie Kinnersley
Charles Ross Lindsey
Gavin Sherlock
Frank Rosenzweig
Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation
BMC Biology
E. coli
Experimental evolution
Whole genome sequencing
Functional genomics
Adaptive genetics
Parallelism
title Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation
title_full Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation
title_fullStr Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation
title_full_unstemmed Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation
title_short Adaptive genetics reveals constraints on protein structure/function by evolving E. coli under constant nutrient limitation
title_sort adaptive genetics reveals constraints on protein structure function by evolving e coli under constant nutrient limitation
topic E. coli
Experimental evolution
Whole genome sequencing
Functional genomics
Adaptive genetics
Parallelism
url https://doi.org/10.1186/s12915-025-02331-7
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