A general model on the origin of biological codes

摘要

For a long time it has been assumed that the rules of the genetic code were determined by chemistry either by stereochemical affinities or by metabolic reactions but the experimental evidence has revealed a totally different reality; it has been shown that any codon can be associated to any amino acid, and this means that there is no deterministic link between them. The genetic code, in other words, is based on arbitrary, or conventional, rules and this raises a formidable problem: how can arbitrary rules exist in Nature? We know that such rules exist in culture, but there is an abyssal difference between biology and culture, because the cultural codes are short-lived, whereas the biological codes are the most conserved entities in evolution. Biological codes, in other words are fundamentally different from cultural codes and we do need a model that makes us understand how they came into being.