TBI 02-08-034 On the Evolution of Primitive Genetic Codes


On the Evolution of Primitive Genetic Codes

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Günter Weberndorfer, Ivo L. Hofacker, Peter F. Stadler

The primordial genetic code probably has been a drastically simplified ancestor of the canonical code that is used by contemporary cells. In order to understand how the present-day code came about we first need to explain how the language of the building plan can change without destroying the encoded information. In this work we introduce a minimal organism model that is based on biophysically reasonable descriptions of RNA and protein, namely secondary structure folding and knowledge based potentials. The evolution of a population of such an organism under competition for a common resource is simulated explicitly at the level of individual replication events. Starting with very simple codes, and hence greatly reduced amino acid alphabets, we observe a diversification of the codes in most simulation runs. The driving force behind this effect is the possibility of producing fitter proteins when the repertoire of amino acids is enlarged.

Keywords: Genetic Code, Evolution, Minimal Organism, Tank Reactor

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