Origins of Life and Evolution of Biospheres

, Volume 38, Issue 6, pp 499–508

Punctuated Chirality

Authors

    • Department of Physics and AstronomyDartmouth College
  • Joel Thorarinson
    • Department of Physics and AstronomyDartmouth College
  • Sara Imari Walker
    • Department of Physics and AstronomyDartmouth College
Origins of Homochirality

DOI: 10.1007/s11084-008-9147-0

Cite this article as:
Gleiser, M., Thorarinson, J. & Walker, S.I. Orig Life Evol Biosph (2008) 38: 499. doi:10.1007/s11084-008-9147-0

Abstract

Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively L-amino acids, while only D-sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high intensity and long duration events may drive achiral initial conditions towards chirality. We argue that life’s homochirality resulted from sequential chiral symmetry breaking triggered by environmental events, thus extending the theory of punctuated equilibrium to the prebiotic realm. Applying our arguments to other potentially life-bearing planetary platforms, we predict that a statistically representative sampling will be racemic on average.

Keywords

HomochiralityPrebiotic chemistryOrigin of lifeEarly planetary environments

Copyright information

© Springer Science+Business Media B.V. 2008