On the statistical distribution of amino acid residue in randomly synthesized peptides

The probability of randomly synthesized peptides having an excess of a given residue Ri (nRi>N/2; N = size of the peptide) decreases strongly with peptide size. For a strong, specific interaction of a Ri, rich peptide with a given sequence of a ribotide chain, peptides should be reasonably large. We discuss how a compromise can be achieved that may have had an important role on the origin of the genetic code.