---
OA_place: repository
OA_type: green
_id: '1571'
abstract:
- lang: eng
  text: Epistatic interactions can frustrate and shape evolutionary change. Indeed,
    phenotypes may fail to evolve when essential mutations are only accessible through
    positive selection if they are fixed simultaneously. How environmental variability
    affects such constraints is poorly understood. Here, we studied genetic constraints
    in fixed and fluctuating environments using the Escherichia coli lac operon as
    a model system for genotype-environment interactions. We found that, in different
    fixed environments, all trajectories that were reconstructed by applying point
    mutations within the transcription factor-operator interface became trapped at
    suboptima, where no additional improvements were possible. Paradoxically, repeated
    switching between these same environments allows unconstrained adaptation by continuous
    improvements. This evolutionary mode is explained by pervasive cross-environmental
    tradeoffs that reposition the peaks in such a way that trapped genotypes can repeatedly
    climb ascending slopes and hence, escape adaptive stasis. Using a Markov approach,
    we developed a mathematical framework to quantify the landscape-crossing rates
    and show that this ratchet-like adaptive mechanism is robust in a wide spectrum
    of fluctuating environments. Overall, this study shows that genetic constraints
    can be overcome by environmental change and that crossenvironmental tradeoffs
    do not necessarily impede but also, can facilitate adaptive evolution. Because
    tradeoffs and environmental variability are ubiquitous in nature, we speculate
    this evolutionary mode to be of general relevance.
acknowledgement: This work is part of the research program of the Foundation for Fundamental
  Research on Matter, which is part of the Netherlands Organization for Scientific
  Research (NWO). M.G.J.d.V. was (partially) funded by NWO Earth and Life Sciences
  (ALW), project 863.14.015. We thank D. M. Weinreich, J. A. G. M. de Visser, T. Paixão,
  J. Polechová, T. Friedlander, and A. E. Mayo for reading and commenting on earlier
  versions of the manuscript and B. Houchmandzadeh, O. Rivoire, and M. Hemery for
  discussions and suggestions on the Markov computation. Furthermore, we thank F.
  J. Poelwijk for sharing plasmid pCascade5 and pRD007 and Y. Yokobayashi for sharing
  plasmid pINV-110. We also thank the anonymous reviewers for remarks on the initial
  version of the manuscript.
article_processing_charge: No
article_type: original
author:
- first_name: Marjon
  full_name: De Vos, Marjon
  id: 3111FFAC-F248-11E8-B48F-1D18A9856A87
  last_name: De Vos
- first_name: Alexandre
  full_name: Dawid, Alexandre
  last_name: Dawid
- first_name: Vanda
  full_name: Šunderlíková, Vanda
  last_name: Šunderlíková
- first_name: Sander
  full_name: Tans, Sander
  last_name: Tans
citation:
  ama: de Vos M, Dawid A, Šunderlíková V, Tans S. Breaking evolutionary constraint
    with a tradeoff ratchet. <i>Proceedings of the National Academy of Sciences</i>.
    2015;112(48):14906-14911. doi:<a href="https://doi.org/10.1073/pnas.1510282112">10.1073/pnas.1510282112</a>
  apa: de Vos, M., Dawid, A., Šunderlíková, V., &#38; Tans, S. (2015). Breaking evolutionary
    constraint with a tradeoff ratchet. <i>Proceedings of the National Academy of
    Sciences</i>. National Academy of Sciences. <a href="https://doi.org/10.1073/pnas.1510282112">https://doi.org/10.1073/pnas.1510282112</a>
  chicago: Vos, Marjon de, Alexandre Dawid, Vanda Šunderlíková, and Sander Tans. “Breaking
    Evolutionary Constraint with a Tradeoff Ratchet.” <i>Proceedings of the National
    Academy of Sciences</i>. National Academy of Sciences, 2015. <a href="https://doi.org/10.1073/pnas.1510282112">https://doi.org/10.1073/pnas.1510282112</a>.
  ieee: M. de Vos, A. Dawid, V. Šunderlíková, and S. Tans, “Breaking evolutionary
    constraint with a tradeoff ratchet,” <i>Proceedings of the National Academy of
    Sciences</i>, vol. 112, no. 48. National Academy of Sciences, pp. 14906–14911,
    2015.
  ista: de Vos M, Dawid A, Šunderlíková V, Tans S. 2015. Breaking evolutionary constraint
    with a tradeoff ratchet. Proceedings of the National Academy of Sciences. 112(48),
    14906–14911.
  mla: de Vos, Marjon, et al. “Breaking Evolutionary Constraint with a Tradeoff Ratchet.”
    <i>Proceedings of the National Academy of Sciences</i>, vol. 112, no. 48, National
    Academy of Sciences, 2015, pp. 14906–11, doi:<a href="https://doi.org/10.1073/pnas.1510282112">10.1073/pnas.1510282112</a>.
  short: M. de Vos, A. Dawid, V. Šunderlíková, S. Tans, Proceedings of the National
    Academy of Sciences 112 (2015) 14906–14911.
date_created: 2018-12-11T11:52:47Z
date_published: 2015-12-01T00:00:00Z
date_updated: 2025-09-23T08:03:27Z
day: '01'
department:
- _id: ToBo
doi: 10.1073/pnas.1510282112
external_id:
  isi:
  - '000365988900054'
  pmid:
  - '26567153'
intvolume: '       112'
isi: 1
issue: '48'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://pmc.ncbi.nlm.nih.gov/articles/PMC4672788/
month: '12'
oa: 1
oa_version: Submitted Version
page: 14906 - 14911
pmid: 1
publication: Proceedings of the National Academy of Sciences
publication_status: published
publisher: National Academy of Sciences
publist_id: '5600'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Breaking evolutionary constraint with a tradeoff ratchet
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 112
year: '2015'
...