The genetic code is not an optimal code in a model taking into account both the biosynthetic relationships between amino acids and their physicochemical properties

We have considered a model for the origin of the genetic code that takes into account the two factors that have determined its evolution: the biosynthetic relationships between amino acids and their physicochemical properties. The model evaluates the biosynthetic relationships between amino acids considering of constraints based on the biosynthetic families of amino acids. These biosynthetic constraints are able to define six subsets of codes-that we have analyzed-in which the evolution of the genetic code might have passed. At the same time, the physicochemical properties of amino acids have been described by means of two scales of polarity, considered solely or combined with the molecular volume of amino acids. Furthermore, we have considered three cost functions.