It now seems very likely that many of the 64 triplets, possibly most of them, may code one amino acid or another, and that in general several distinct triplets may code one amino acid.
It is one of the more striking generalizations of biochemistry – which surprisingly is hardly ever mentioned in the biochemical textbooks – that the twenty amino acids and the four bases, are, with minor reservations, the same throughout Nature.
It is not easy to convey, unless one has experienced it, the dramatic feeling of sudden enlightenment that floods the mind when the right idea finally clinches into place.
A comparison between the triplets tentatively deduced by these methods with the changes in amino acid sequence produced by mutation shows a fair measure of agreement.
How is the base sequence, divided into codons? There is nothing in the backbone of the nucleic acid, which is perfectly regular, to show us how to group the bases into codons.
If, for example, all the codons are triplets, then in addition to the correct reading of the message, there are two incorrect readings which we shall obtain if we do not start the grouping into sets of three at the right place.
Exploratory research is really like working in a fog. You don’t know where you’re going. You’re just groping. Then people learn about it afterwards and think how straightforward it was.
