Supporting information for "Flexible genes establish widespread bacteriophage pan-genomes in cryoconite hole ecosystems"

  • Christopher M. Bellas (Creator)
  • Declan C. Schroeder (Creator)
  • Arwyn Edwards (Creator)
  • Gary L. Barker (Creator)
  • Alexandre Magno Anesio (Aarhus University) (Creator)



Bacteriophage genomes rapidly evolve via mutation and horizontal gene transfer to counter evolving bacterial host defenses; such arms race dynamics should lead to divergence between phages from similar, geographically isolated ecosystems. However, near-identical phage genomes can reoccur over large geographical distances and several years apart, conversely suggesting many are stably maintained. Here, we show that phages with near-identical core genomes in distant, discrete aquatic ecosystems maintain diversity by possession of numerous flexible gene modules, where homologous genes present in the pan-genome interchange to create new phage variants. By repeatedly reconstructing the core and flexible regions of phage genomes from different metagenomes, we show a pool of homologous gene variants co-exist for each module in each location, however, the dominant variant shuffles independently in each module. These results suggest that in a natural community, recombination is the largest contributor to phage diversity, allowing a variety of host recognition receptors and genes to counter bacterial defenses to co-exist for each phage.
Date made available14 Sept 2002
PublisherPrifysgol Aberystwyth | Aberystwyth University

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