An early step had been the landmark discovery by
Griffith [13] of the in vivo transformation of
Streptococcus pneumoniae in mice. This was the prelude
to the demonstration by Avery and his colleagues [14]
that Griffith’s transforming substance was, in fact, DNA
and it was also the first demonstration of genetic transfer
in bacteria. The resolution of the structure of DNA as a
double helix [2] and the recognition that this structure has
genetic implications [15] led to the deciphering of the
genetic code that determines protein structure. The transcription
of the DNA message to messenger RNA and
subsequent translation into the amino acid sequence of
proteins was recognized as sufficiently fundamental that
it became known as a ‘dogma’, though like all dogma it
did not long survive unmodified.