Life's chirality from prebiotic environments

Marcelo Gleiser, Sara Walker

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

A key open question in the study of life is the origin of biomolecular homochirality: almost every life-form on Earth has exclusively levorotary amino acids and dextrorotary sugars. Will the same handedness be preferred if life is found elsewhere? We review some of the pertinent literature and discuss recent results suggesting that life's homochirality resulted from sequential chiral symmetry breaking triggered by environmental events. In one scenario, autocatalytic prebiotic reactions undergo stochastic fluctuations due to environmental disturbances, in a mechanism reminiscent of evolutionary punctuated equilibrium: shortlived destructive events may lead to long-term enantiomeric excess. In another, chiral-selective polymerization reaction rates influenced by environmental effects lead to substantial chiral excess even in the absence of autocatalysis. Applying these arguments to other potentially life-bearing platforms has implications to the search for extraterrestrial life: we predict that a statistically representative sampling of extraterrestrial stereochemistry will be racemic (chirally neutral) on average.

Original languageEnglish (US)
Pages (from-to)287-296
Number of pages10
JournalInternational Journal of Astrobiology
Volume11
Issue number4
DOIs
StatePublished - Oct 1 2012

Keywords

  • Astrobiology
  • Chirality
  • Origin of life
  • Prebiotic chemistry
  • SPASA 2011

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)

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