Robustness of compositional heredity to the growth and division dynamics of prebiotic compartments

An important transition after the origin of life was the first emergence of a Darwinian population, self-reproducing entities exhibiting differential reproduction, phenotypic variation, and inheritance of phenotypic traits. The simplest system we can imagine to have these properties would consist of a compartmentalized autocatalytic reaction system that exhibits two growth states with different chemical compositions. Identifying the chemical composition as the phenotype, this accounts for two of the properties. However, it is not clear what are the necessary conditions for such a chemical system to exhibit inheritance of the compositional states upon growth and division of the compartment. We show that for a general class of autocatalytic chemical systems subject to serial dilution, the inheritance of compositional information only occurs when the time interval between dilutions is below a critical threshold that depends on the efficiency of the catalytic reactions. Further, we show that these thresholds provide rigorous bounds on the properties required for the inheritance of the chemical compositional state for general growth and division cycles. Our result suggests that a serial dilution experiment, which is much easier to set up in a laboratory, can be used to test whether a given autocatalytic chemical system can exhibit heredity. Lastly, we apply our results to a realistic autocatalytic system based on the Azoarcus ribozyme and suggest a protocol to experimentally test whether this system can exhibit heredity.
Comment: 30 pages, 22 figures