In silico simulations reveal that replicators with limited dispersal evolve towards higher efficiency and fidelity

Abstract

The emergence of functional replicases, acting quickly and with high accuracy, was crucial to the origin of life. Although where the first RNA molecules came from is still unknown, it is nevertheless assumed that catalytic RNA enzymes (ribozymes) with replicase function emerged at some early stage of evolution. The fidelity of copying is especially important because the mutation load limits the length of replicating templates that can be maintained by natural selection. An increase in template length is disadvantageous for a fixed digit copying fidelity, however, longer molecules are expected to be better replicases. An iteration for longer molecules with better replicase function has been suggested and analysed mathematically. Here we show that more efficient replicases can spread, provided they are adsorbed to a prebiotic mineral surface. A cellular automaton simulation reveals that copying fidelity, replicase speed and template efficiency all increase with evolution, despite the presence of molecular parasites, essentially because of reciprocal atruism ('within-species mutualism') on the surface, thus making a gradual improvement of replicase function more plausible.

“Synergistic selection”: A Darwinian frame for the evolution of complexity

“…R 0 is a parasite that is enzymatically inefficient but replicates when helped by R faster than R itself (Szabó et al, 2002). This system cannot be saved from the spread of R 0 by random grouping because R pays an absolute cost.…”

Competitive exclusion and limiting similarity: A unified theory

“…Czárán & Bartha (1989, 1992, Czárán (1998) investigated diversity arising from complex spatio-temporal patterns. Tél et al (2000), Károlyi et al (2000Károlyi et al ( , 2002, Szabó et al (2002), Scheuring et al (2003) studied coexistence in chaotic flows.…”

The origin of replicators and reproducers

“…Absorption to mineral surfaces was hypothesized to help replicases find their useful colleagues in the immediate neighbourhood ( Joyce & Orgel 1999). A cellular automaton simulation revealed that copying fidelity, replicase speed and template efficiency could increase by evolution, despite the presence of molecular parasites, essentially owing to reciprocal altruism on the surface, thus making the scenario for a gradual improvement of replicase function more plausible (Szabó et al 2002).…”