Nirenberg and Leder experiment

Oswald Avery discovered that the substance responsible for producing inheritable change in the disease-causing bacteria was neither a protein nor a lipid, rather deoxyribonucleic acid (DNA).

In 1953, with the help of Maurice Wilkins and Rosalind Franklin’s X-ray crystallography, James Watson and Francis Crick proposed DNA is structured as a double helix.

[2] Seymour Benzer in the late 1950s had developed an assay using phage mutations which provided the first detailed linearly structured map of a genetic region.

[5] They correctly concluded that the code is degenerate, that triplets are not overlapping, and that each nucleotide sequence is read from a specific starting point.

For example, a long RNA could be made that had a ratio of C to U of 2:1, and so would contain codons CCU, CUC, UCC at high frequency.

Once high enough concentrations of mRNA were produced, degradation and reformation of polymerase products was accomplished through enzymatic processes.

Working independently, Khorana had mastered the synthesis of nucleic acids, and Holley had discovered the exact chemical structure of transfer-RNA.

The New York Times said of Nirenberg's work that "the science of biology has reached a new frontier," leading to "a revolution far greater in its potential significance than the atomic or hydrogen bomb."

For example, Arne Tiselius, the 1948 Nobel Laureate in Chemistry, asserted that knowledge of the genetic code could "lead to methods of tampering with life, of creating new diseases, of controlling minds, of influencing heredity, even perhaps in certain desired directions.