Abstract
Explaining origins of life requires us to explain how self-replication arises. Specifically, how can self-replicating entities develop spon-taneously from chemical reaction systems in which no reaction is self-replicating? Previously proposed mathematical models either supply a framework for a minimal living system or only consider cat-alyzed reactions, and thus fail to provide a comprehensive theory. We set up a general model for chemical reaction systems that properly accounts for energetics, kinetics and conservation laws. We find that (1) some systems are collectively-catalytic (e.g., the citric acid cycle), while some others self-replicate as a whole (e.g., the formose reaction); (2) side reactions do not always inhibit such systems; (3) many alternative chemical universes often contain one or more such systems; (4) it is possible to construct a self-replicating system where the entropy of some parts spontaneously decreases, in a manner similar to that discussed by Schrödinger; (5) complex self-replicating molecules can emerge spontaneously and relatively easily from simple chemical reaction systems through a sequence of transitions. Together these results start to explain the origins of prebiotic evolution.
Author contributions
Y.L. and D.S. designed research; Y.L. performed research; and Y.L. and D.S. wrote the paper.