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Article Dans Une Revue Proceedings of the National Academy of Sciences of the United States of America Année : 2013

Mutation rate dynamics in a bacterial population reflect tension between adaptation and genetic load.

Sébastien Wielgoss
  • Fonction : Auteur
Michael J Wiser
  • Fonction : Auteur
W James Dittmar
  • Fonction : Auteur
Stéphane Cruveiller
  • Fonction : Auteur
Béatrice Chane-Woon-Ming
  • Fonction : Auteur
  • PersonId : 1089431
Claudine Médigue
Richard E Lenski
  • Fonction : Auteur

Résumé

Mutations are the ultimate source of heritable variation for evolution. Understanding how mutation rates themselves evolve is thus essential for quantitatively understanding many evolutionary processes. According to theory, mutation rates should be minimized for well-adapted populations living in stable environments, whereas hypermutators may evolve if conditions change. However, the long-term fate of hypermutators is unknown. Using a phylogenomic approach, we found that an adapting Escherichia coli population that first evolved a mutT hypermutator phenotype was later invaded by two independent lineages with mutY mutations that reduced genome-wide mutation rates. Applying neutral theory to synonymous substitutions, we dated the emergence of these mutations and inferred that the mutT mutation increased the point-mutation rate by ∼150-fold, whereas the mutY mutations reduced the rate by ∼40-60%, with a corresponding decrease in the genetic load. Thus, the long-term fate of the hypermutators was governed by the selective advantage arising from a reduced mutation rate as the potential for further adaptation declined.

Dates et versions

hal-00800700 , version 1 (14-03-2013)

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Citer

Sébastien Wielgoss, Jeffrey E Barrick, Olivier Tenaillon, Michael J Wiser, W James Dittmar, et al.. Mutation rate dynamics in a bacterial population reflect tension between adaptation and genetic load.. Proceedings of the National Academy of Sciences of the United States of America, 2013, 110 (1), pp.222-7. ⟨10.1073/pnas.1219574110⟩. ⟨hal-00800700⟩
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