"The origin of the genetic code"

Date:
1968
Reference:
PP/CRI/H/4/15
Catalogue details

Licence: In copyright

Credit: "The origin of the genetic code". Source: Wellcome Collection.

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    That is y/all^jtha,. sugars (ribo a&i*ttT airtcTs (with the In examining Table I, however, one is apt to take all these characteristics for granted. What, then, is special about the actual details of the genetic code? í he main features, which have frequently been commented on, are:- 4. The 20 amino acids are not distributed at random among the 64 triplets. In fact several rules can easily be deduced from the Table. Por example, Y a) XYTJ and X$C always code the same amino acid. b) XYA and XYG often code the same amino acid. The rare amino acid3, methionine and tryptophan, which have only one codon each, appear to be exceptions to this rule. c) In half the cases (8 out of 16) XY*represents a single amino acid, where the * implies that all four bases are possible. d) In most cases the codons representing a single amino acid start with the same pair of bases. Thus the two codons for histidine both start with CA. There are