Selection for mutational robustness in finite populations

J Theor Biol. 2006 Nov 21;243(2):181-90. doi: 10.1016/j.jtbi.2006.06.020. Epub 2006 Jun 30.


We investigate the evolutionary dynamics of a finite population of RNA sequences replicating on a neutral network. Despite the lack of differential fitness between viable sequences, we observe typical properties of adaptive evolution, such as increase of mean fitness over time and punctuated-equilibrium transitions, after initial mutation-selection balance has been reached. We find that a product of population size and mutation rate of approximately 30 or larger is sufficient to generate selection pressure for mutational robustness, even if the population size is orders of magnitude smaller than the neutral network on which the population resides. Our results show that quasispecies effects and neutral drift can occur concurrently, and that the relative importance of each is determined by the product of population size and mutation rate.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Base Sequence
  • Evolution, Molecular*
  • Models, Genetic
  • Mutation*
  • Neural Networks, Computer
  • Nucleic Acid Conformation
  • Population Density
  • RNA / genetics
  • Selection, Genetic*


  • RNA