Speculations on the evolution of the genetic code

Orig Life. 1975 Jul;6(3):423-7. doi: 10.1007/BF01130344.


An evolutionary scheme is postulated in which the bases enter the genetic code in a definite temporal sequence and the correlated amino acids are assigned definite functions in the evolving system. The scheme requires a singlet code (guanine coding for glycine) evolving into a doublet code (guanine-cytosine doublet coding for gly (GG), ala (GC), arg (CG), pro (CC). The doublet code evolves into a triplet code. Polymerization of nucleotides is thought to have been by block polymerization rather than by a template mechanism. The proteins formed at first were simple structural peptides. No direct nucleotide-amino acid stereo-chemical interaction was required. Rather an adaptor-type indirect mechanism is thought to have been functioning since the origin.

MeSH terms

  • Biological Evolution
  • Genetic Code*
  • Protein Biosynthesis
  • Transcription, Genetic