Divergent evolution peaks under intermediate population bottlenecks during bacterial experimental evolution

Tom Vogwill*, Robyn L. Phillips, Danna R. Gifford, R. Craig MacLean*

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Citations (Scopus)
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Abstract

There is growing evidence that parallel molecular evolution is common, but its causes remain poorly understood. Demographic parameters such as population bottlenecks are predicted to be major determinants of parallelism. Here, we test the hypothesis that bottleneck intensity shapes parallel evolution by elucidating the genomic basis of adaptation to antibiotic-supplemented media in hundreds of populations of the bacterium Pseudomonas fluorescens Pf0-1. As expected, bottlenecking decreased the rate of phenotypic and molecular adaptation. Surprisingly, bottlenecking had no impact on the likelihood of parallel adaptive molecular evolution at a genome-wide scale. However, bottlenecking had a profound impact on the genes involved in antibiotic resistance. Specifically, under either intense or weak bottlenecking, resistance predominantly evolved by strongly beneficial mutations which provide high levels of antibiotic resistance. In contrast with intermediate bottlenecking regimes, resistance evolved by a greater diversity of genetic mechanisms, significantly reducing the observed levels of parallel genetic evolution. Our results demonstrate that population bottlenecking can be a major predictor of parallel evolution, but precisely how may be more complex than many simple theoretical predictions.

Original languageEnglish
Article number20160749
Number of pages8
JournalProceedings of the Royal Society of London. B, Biological Sciences
Volume283
Issue number1835
Early online date27 Jul 2016
DOIs
Publication statusPublished - 27 Jul 2016

Keywords

  • experimental evolution
  • population bottlenecks
  • evolutionary rescue
  • genome sequencing
  • parallel evolution
  • ANTIBIOTIC-RESISTANCE
  • BENEFICIAL MUTATIONS
  • PSEUDOMONAS-AERUGINOSA
  • CONVERGENT EVOLUTION
  • ESCHERICHIA-COLI
  • PARALLEL EVOLUTION
  • POSITIVE SELECTION
  • FITNESS LANDSCAPES
  • SEQUENCING DATA
  • ADAPTATION

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

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