Self-description and the origin of the genetic code

Abstract

The genetic code presents an important conceptual challenge within the broader context of the origin of life. Translation of genetic information captures a fundamental property of living systems, i.e. the ability of decoding proteins (e.g. aminoacyl-tRNA synthetases) to reproduce themselves from self-contained RNA/DNA descriptors. Silvano Colombano and I, as graduate students with Howard Pattee in the 1970s, focused on achieving this closure of self-description and self-reproduction in the genetic code. Simulation and analysis of competitive models that allowed alternate code assignments, exploring initial conditions, arbitrary descriptor–catalyst relationships, and degree of non-linearity, indicated that these dynamical systems undergo bifurcations, transforming initial ambiguous stable states to unstable states. New, stable, steady states, progressively closer to a code, became available as the descriptor parameters were varied. The efficiency of utilization of raw materials for the production of a coding family of catalysts is proposed as a selection criterion that drives such systems towards a coded state.