T.M. SONNEBORN’s scientific contributions

Part I of this paper deals with the amount of degeneracy in the genetic code or, looked at in reverse, the amount of nonsense. Section A considers the experimental evidence and suggests (a) that technical difficulties have prevented assigning meaning to the still unassigned triplets and (b) that the validity of the earlier evidences for nonsense triplets may be questioned in the light of recent discoveries. Complete degeneracy of the code and total absence of nonsense have not yet been excluded. Section B comes to the conclusion, on the basis of general evolutionary considerations, that natural selection would be expected to establish and preserve a completely degenerate code. Section C points out that different nondegenerate codes differ greatly in the builtin frequency of nonsense mutations by single base substitutions.