Selection for Motifs Within Protocells: A Computational Study in Prelife

Abstract

The transition from pre-life, where self-replication does not occur, to life, where self-replication and Darwinian evolution occur, has not yet been fully delineated. Membranes, forming protocells, have been shown to be important for this transition due to their ability to contain reactions which are unfavorable in a well-mixed solution. Protocells also support the emergence of cooperative behavior. Intensive theoretical and experimental research has focused on the evolution of replicating information-carrying polymers (e.g. RNA) within protocells. Despite this treatment, we are still relatively ignorant about the dynamics by which elongating polynucleotides, absent direct replication, produce behavior that leads to cellular complexity. In this study, we conduct a computational experiment to examine the effect that polymers with a simple mechanism — biasing the monomer content of elongating strands — have on the dynamics of the system. We show that these functional polymers acquire a selective advantage in the absence of template-directed replication and also demonstrate that complex behavior (i.e. cooperator/competitor dynamics) can emerge from the system.