Prebiotic Chemistry in the Wild: How Geology Interferes with the Origins of Life

A plausible explanation for the origin of life must satisfy constraints imposed by both organic chemistry and early Earth geochemistry. However, the full scope of geochemical parameter space is rarely considered by either theoretical or experimental models of abiogenesis. Here we propose a novel approach, which can make maximum use of available data. We posit that constructive and destructive geochemical interferences with proposed prebiotic reaction schemes can be used to restrict plausible environmental parameter space for the origin of life. Our approach is demonstrated by exploring parameter space for dehydration reactions. Such reactions are universally important in extant biochemistry and all proposed prebiotic reaction schemes, yet challenging to perform under plausible conditions. We specifically explore a minimal pathway for RNA synthesis (formaldehyde; ribose; ribose phosphate; adenosine monophosphate; RNA). Based on assembled thermodynamic and geochemical constraints, we identify that low water activity is a key constructive interference in prebiotic chemistry. Critically, the manner in which low water activity is achieved can strongly discriminate between different environmental scenarios. Exploring interference chemistry is hence an effective means of discriminating between competing origin of life scenarios.