In 1967, two years after the date of this letter, Crick, Sydney Brenner, and Alan Garen determined that the amber and ochre codons mentioned in the last paragraph (the triplets UAG and UAA, respectively) signal the termination of the polypeptide chain. They were called nonsense codons because it became clear from experiments with certain phage mutants that they do not specify any amino acid during protein synthesis. The names amber and ochre were assigned to them randomly by researchers.. NOTE: The date was mistakenly typed as "7th January 1964." The actual date of this letter is 7 January 1965.
Copyright:
This item may be under copyright protection; contact the copyright owner for permission before re-use.