title: Validating viral quasispecies with digital organisms: a re-examination of the critical mutation rate.
abstract: BACKGROUND
  In this report we re-examine some recent experiments with digital organisms to test some predictions of quasispecies theory. These experiments revealed that under high mutation rates populations of less fit organisms previously adapted to such high mutation rates were able to outcompete organisms with higher average fitness but adapted to low mutation rates.
  
  
  RESULTS
  We have verified that these results do hold in the original conditions and, by extending the set of initial parameters, we have also detected that the critical mutation rate was independent of population size, a result that we have found to be dependent on a different, contingent factor, the initial fitness vector. Furthermore, in all but one case, the critical mutation rate is higher than the error threshold, a key parameter in quasispecies theory, which prevents its extrapolation to natural viral populations.
  
  
  CONCLUSIONS
  From these results we conclude that digital organisms are useful tools for investigating evolutionary patterns and processes including some predictions from the quasispecies theory.
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain. inaki.comas@uv.es <inaki.comas@uv.es>
authors.forename: Iñaki
authors.initials: I
authors.lastname: Comas
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
authors.forename: Fernando
authors.initials: F
authors.lastname: González-Candelas
mesh_terms: D000220:Adaptation, Biological; D005075:Biological Evolution; D003198:Computer Simulation; D004463:Ecology; D019143:Evolution, Molecular; D005814:Genes, Viral; D014644:Genetic Variation; D016678:Genome; D008954:Models, Biological; D008957:Models, Genetic; D015233:Models, Statistical; D009154:Mutation; D012641:Selection, Genetic; D013045:Species Specificity; D014780:Viruses / Q000235:genetics*