title: Speculations on the evolution of the genetic code IV.  The evolution of the aminoacyl-tRNA synthetases.
abstract: An evolutionary scheme is postulated in which a primitive code, involving only guanine and cytosine, would code for glycine(GG.), alanine(GC.), arginine(CG.) and proline(CC.).  There evolves from this primitive code families of related amino acids as the code expands.  The evolution of the aminoacyl-tRNA synthetases are considered to be indicators for the evolution of the genetic code.  The postulated model for the evolution of the genetic code is used to give an evolutionary interpretation to the recent work on the structure and sequences of the aminoacyl-tRNA synthetases.
authors.affiliation: Institute for Advanced Studies in Biology, Berkeley, CA 94707, USA.
authors.forename: H
authors.initials: H
authors.lastname: Hartman
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000145:classification / Q000235:genetics*; D000604:Amino Acyl-tRNA Synthetases / Q000145:classification* / Q000235:genetics*; D003062:Codon; D019143:Evolution, Molecular; D005815:Genetic Code
chemical_list: D000596:Amino Acids; D003062:Codon; D000604:Amino Acyl-tRNA Synthetases