iv) One basis for messenger RNA which transfers information from genes to proteins was appearance in bacteria after phage-infection of a new RNA whose base composition corresponds to that of the virus DNA, by Elliot Volkin et al.31 Elucidation of repression provided the second basis. A requirement of RNA synthesis for protein production had been shown; mutants of E. coli deprived of purines or pyrimidines stopped making proteins as well as nucleic acids, reported by Pardee in 1954 as ��. continuous formation of RNA is essential for protein formation.�32 An unstable intermediate between gene and enzyme was proposed in 1958: �DNA does make an intermediate carrier of information, perhaps RNA,�33 this is in accord with an unstable intermediate.28 Pardee and Louise Prestidge in 1961 found that on/off kinetics of b-galactosidase induction are very rapid, with a 3 min half-life.34 mRNA was identified in 1961 by two laboratories.28,35