Evolutionary layering and the limits to cellular perfection

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Although observations from biochemistry and cell biology seemingly illustrate hundreds of examples of exquisite molecular adaptations, the fact that experimental manipulation can often result in improvements in cellular infrastructure raises the question as to what ultimately limits the level of molecular perfection achievable by natural selection. Here, it is argued that random genetic drift can impose a strong barrier to the advancement of molecular refinements by adaptive processes. Moreover, although substantial improvements in fitness may sometimes be accomplished via the emergence of novel cellular features that improve on previously established mechanisms, such advances are expected to often be transient, with overall fitness eventually returning to the level before incorporation of the genetic novelty. As a consequence of such changes, increased molecular/cellular complexity can arise by Darwinian processes, while yielding no long-term increase in adaptation and imposing increased energetic and mutational costs.

Original languageEnglish (US)
Pages (from-to)18851-18856
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number46
StatePublished - Nov 13 2012
Externally publishedYes


  • Cellular evolution
  • Genetic load
  • Nonadaptive evolution
  • Robustness

ASJC Scopus subject areas

  • General


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