Journal of Molecular Evolution

, Volume 72, Issue 3, pp 283–295

Monomer Abundance Distribution Patterns as a Universal Biosignature: Examples from Terrestrial and Digital Life

  • Evan D. Dorn
  • Kenneth H. Nealson
  • Christoph Adami

DOI: 10.1007/s00239-011-9429-4

Cite this article as:
Dorn, E.D., Nealson, K.H. & Adami, C. J Mol Evol (2011) 72: 283. doi:10.1007/s00239-011-9429-4


Organisms leave a distinctive chemical signature in their environment because they synthesize those molecules that maximize their fitness. As a result, the relative concentrations of related chemical monomers in life-bearing environmental samples reflect, in part, those compounds’ adaptive utility. In contrast, rates of molecular synthesis in a lifeless environment are dictated by reaction kinetics and thermodynamics, so concentrations of related monomers in abiotic samples tend to exhibit specific patterns dominated by small, easily formed, low-formation-energy molecules. We contend that this distinction can serve as a universal biosignature: the measurement of chemical concentration ratios that belie formation kinetics or equilibrium thermodynamics indicates the likely presence of life. We explore the features of this biosignature as observed in amino acids and carboxylic acids, using published data from numerous studies of terrestrial sediments, abiotic (spark, UV, and high-energy proton) synthesis experiments, and meteorite bodies. We then compare these data to the results of experimental studies of an evolving digital life system. We observe the robust and repeatable evolution of an analogous biosignature in a digital lifeform, suggesting that evolutionary selection necessarily constrains organism composition and that the monomer abundance biosignature phenomenon is universal to evolved biosystems.


Artificial life Amino acids Carboxylic acids Astrobiology Exobiology Evolution Meteorites 

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Evan D. Dorn
    • 1
  • Kenneth H. Nealson
    • 2
  • Christoph Adami
    • 3
    • 4
  1. 1.Digital Life Laboratory 136-93California Institute of TechnologyPasadenaUSA
  2. 2.Department of Earth SciencesUniversity of Southern CaliforniaLos AngelesUSA
  3. 3.Keck Graduate Institute of Applied Life ScienceClaremontUSA
  4. 4.BEACON Center for Evolution in Action, Michigan State UniversityEast LansingUSA

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