title: A sequential "2-1-3" model of genetic code evolution that explains codon constraints.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Massey
mesh_terms: D003062:Codon / Q000235:genetics*; D019143:Evolution, Molecular; D008957:Models, Genetic; D016364:Reading Frames
chemical_list: D003062:Codon