title: Robustness promotes evolvability of thermotolerance in an RNA virus.
abstract: BACKGROUND
  The ability for an evolving population to adapt to a novel environment is achieved through a balance of robustness and evolvability. Robustness is the invariance of phenotype in the face of perturbation and evolvability is the capacity to adapt in response to selection. Genetic robustness has been posited, depending on the underlying mechanism, to either decrease the efficacy of selection, or increase the possibility of future adaptation. However, the true effect of genetic robustness on evolvability in biological systems remains uncertain.
  
  
  RESULTS
  Here we demonstrate that genetic robustness increases evolvability of thermotolerance in laboratory populations of the RNA virus phi6. We observed that populations founded by robust clones evolved greater resistance to heat shock, relative to populations founded by brittle (less-robust) clones. Thus, we provide empirical evidence for the idea that robustness can promote evolvability in this environment, and further suggest that evolvability can arise indirectly via selection for robustness, rather than through direct selective action.
  
  
  CONCLUSIONS
  Our data imply that greater tolerance of mutational change is associated with virus adaptability in a new niche, a finding generally relevant to evolutionary biology, and informative for elucidating how viruses might evolve to emerge in new habitats and/or overcome novel therapies.
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520-8106, USA. robert.mcbride@yale.edu
authors.forename: Robert C
authors.initials: RC
authors.lastname: McBride
authors.forename: C Brandon
authors.initials: CB
authors.lastname: Ogbunugafor
authors.forename: Paul E
authors.initials: PE
authors.lastname: Turner
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D017126:Bacteriophage phi 6 / Q000235:genetics* / Q000254:growth & development*; D019143:Evolution, Molecular; D014644:Genetic Variation; D006358:Hot Temperature; D044224:Pseudomonas syringae / Q000821:virology; D012367:RNA, Viral / Q000235:genetics*; D012641:Selection, Genetic; D017423:Sequence Analysis, RNA; D010948:Viral Plaque Assay
chemical_list: D012367:RNA, Viral