The evolution of robustness and fragility during long- term bacterial adaptation

• 成果类型: Article
• 署名作者: Chihoub, Doha; Pintard, Coralie; Lenski, Richard E.; Tenaillon, Olivier; Couce, Alejandro
• 署名单位: Universidad Politecnica de Madrid; Institut National de la Sante et de la Recherche Medicale (Inserm); Universite Paris Cite; Michigan State University; Universite Paris Cite; Institut National de la Sante et de la Recherche Medicale (Inserm)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10572
• DOI: 10.1073/pnas.2501901122
• 发表日期: 2025-04-22
• 关键词: fitness; selection

摘要

Theory predicts that well-adapted populations may evolve mechanisms to counteract the inevitable influx of deleterious mutations. While mutational robustness can be directly selected in the laboratory, evidence for its spontaneous evolution during general adaptation is mixed. Moreover, whether robustness evolves to include pleiotropic effects remains largely unexplored. Here, we studied the effects of point mutations in the RNA polymerase of Escherichia coli over a 15,000-generation adaptive trajectory. Fitness effects of both beneficial and deleterious mutations were attenuated in fitter backgrounds. In contrast, pleiotropic effects became more severe and widespread with greater adaptation. These results show that trade-offs between robustness and fragility can evolve in regulatory networks, regardless of whether driven by adaptive or nonadaptive processes. More broadly, they illustrate how adaptation can generate hidden variability, with unpredictable evolutionary consequences in new environments.