An article that addresses this question:
Excerpt of Abstract
The genetic code is nearly universal, and the arrangement of the codons in the standard codon table is highly non-random. The three main concepts on the origin and evolution of the code are the stereochemical theory, according to which codon assignments are dictated by physico- chemical affinity between amino acids and the cognate codons (anticodons); the coevolution theory, which posits that the code structure coevolved with amino acid biosynthesis pathways; and the error minimization theory under which selection to minimize the adverse effect of point mutations and translation errors was the principal factor of the code’s evolution. These theories are not mutually exclusive and are also compatible with the frozen accident hypothesis, i.e., the notion that the standard code might have no special properties but was fixed simply because all extant life forms share a common ancestor, with subsequent changes to the code, mostly, precluded by the deleterious effect of codon reassignment.
I am looking for people to read the article and discuss. For instance, it’s not clear to me how a genetic code can be derived by “Evolution”, meaning darwinian natural selection, since that would require a library (such as DNA) to store the instructions for building the code. My assumption is that a DNA code and a storage library such as DNA are basic mechanisms that make evolution possible, and thus it must be explained without evolution. Is this true?