Codon 1965

Date:
1965
Reference:
PP/CRI/H/3/16
Catalogue details

Licence: In copyright

Credit: Codon 1965. Source: Wellcome Collection.

    10/75
    In addition I wonder about UGA.. The results of Nirenberg et al. (1965) suggest that it may not be Tryp. Oould it be Cys, so that Cys is coded by U C Ü ü C G U C A If so then the ochre triplet should revert to Cys but not to Tryp. This should be easy to discover. Por those cases in which all bases (in the third position of the codon) code the same amino acid Inosine might or might not occur. We can code all four bases with a minimum of two S-RNA's using either anticodon codon C G and it is of course possible that more than the minimum number is used. Thus Inosine could occur in the anticodons of some species, but not in others. Evolution of the Code I note that Theory 4 offers an easy way to change the code somewhat during Evolution, by using ambiguous codons. (I shall not discuss here the origin of the code. ) As an example consider the following: Anticodon Codon Amino Acid GAU AO? lieu (A AU AUU lieu) UAU AU£ Met (CAU AUG Met ) changing to (GAU AU» lieu) ( ( AAU AUU lieu)) U IAU AUC lieu i.e. AUA codes A both lieu UAU < Met and Met CAU AUG Met changing to (GAU < lieu) ((AAU AUU lieu)) no ambiguity; the IAU U AUC lieu only codon for A Met is now AUG CAU AUG Met The brackets show optional cases.