The Genetic Code and the Origin of Life formatIsbn:Hardcover 9780306478437 Giampaolo Noja (Italy O.P Giampaolo Noja (Italy the lakes and mires it was not until the early 1950s that the Hershey Chase experiments provided a more direct demonstration of this role The 1956 dis covery by David Davies and myself showed that polyadenylic acid and polyuridylic acid could form a double helical RNA molecule but that it differed somewhat from DN A A large number of experiments were subsequendy carried out with synthetic polyribonucleotides which illustrated that RNA could form even more complicated helical structures in which the specificity of hydrogen bonding was the key element in determining the molecular conformation