Thermodynamic approach to a possible theory of the evolution of a genetic code.

One of the distinctive features of a biological system is its remoteness from equilibrium: for the treatment of the information exchanged by these systems with the external world the concept of information amount is not sufficient because for nonequilibrium systems we need further specifications about information, i.e. its value. We defined the information value for a genetic code. The comparison of the results we had applying such a definition to the three genetic codes found in nature shows that our definition described the system of transmission and reception of information in a biological organism very well and that the information value of a genetic code can be considered as an index of its efficiency, i.e. of its ability to minimize the effects of a mutation of the genotype on the phenotype. Otherwise, our results show that the information value, and hence the efficiency of the three known codes is the same and suggest that the prerequisite of the evolution of the codes is the preservation of this value.