Early Prebiotic Reaction Networks

Dear Colleagues,

We are pleased to present this Special Issue focused on abiotic reaction networks. These reactions have received limited attention from the origin-of-life community over the past decade, despite several developments that warrant renewed interest. This Special Issue brings together recent work in this area to explore its relevance to early chemical evolution. 

Historically, prebiotic research has focused heavily on the chemistry of peptides, nucleic acids, and lipids. While these biological polymers are essential to life, they primarily serve regulatory functions within cells—compartmentalizing, controlling, and catalyzing reactions among smaller molecules. In contrast, many of these small molecules themselves—such as central metabolites and redox cofactors—are remarkably conserved across the tree of life, suggesting a deep, possibly prebiotic origin. 

Harold Morowitz and George Whitesides have referred to these conserved molecular patterns as “chemical fossils”—chemical remnants that may trace back to the earliest stages of prebiotic chemistry and constrain the scope of chemistry for life on Earth, and possibly elsewhere in the Universe. This list often includes thioester compounds, citric acid cycle intermediates, isoprenoids, quinones and other redox cofactors, and the high potassium-to-sodium ratio maintained across cellular membranes in most living organisms. 

Many of these chemical fossils engage in reactions that occur without enzymatic catalysis and display surprisingly complex behaviors. Examples include autocatalysis, observed in thioester and quinone redox chemistry, resulting in reaction networks that give rise to pattern formation, oscillations, and other nonlinear dynamics.

The reactions explored in this Special Issue involve a limited number of simple components—many of which are known to exist widely across the universe. Some steps in these networks have even been inherited by modern cells and are integrated into broader biogeochemical cycles that shape planetary systems.

Despite their significance, reaction networks formed by small molecules have received less attention from the astrobiology and origin-of-life communities than they deserve. A deeper understanding of the scope, robustness, and emergent complexity of these systems is essential—not only to grasp life’s potential boundaries on Earth but also to expand our expectations for life elsewhere

Dr. Olga Taran
Dr. Paul J. Bracher
Guest Editors

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• thioesters
• autocatalytic reactions
• redox cycling
• chemical fossils
• TCA cycle analogues