170 NUCLEIC ACIDS, DECODING, ETC. 



relationship between their abundance — and also between the 

 DNA type, AT or GC — and the coding efficiency of a DNA. 



But before engaging in much work, I thought the situation 

 over. And a short time ago I underwent a sort of conversion 

 which lasted for one week. I decided to believe everything — but 

 everything — that I read in the literature. I swallowed all bio- 

 chemical snapshots, preliminary communications, all press re- 

 leases that punctuated the, more or less, friendly competition 

 between different laboratories — in other words, the entire sour 

 grapevine. I followed the international spelling bee with open- 

 mouthed admiration. I became what you might call a molecular 

 fundamentalist. And this is what I encountered during my brief 

 pilgrimage through the bible-belt of molecular biology. The 

 dogma stated: DNA makes "messenger" RNA, makes protein. 

 "Fine", I said; but though temporarily a True Believer, I had 

 not stopped being a chemist. So I reasoned: "Messenger" RNA 

 is said to be a complete image of DNA, mirroring its base-pairing 

 and other regularities; A = U; G = C, and so on. The amino 

 acid composition of many proteins is known precisely, and in 

 many instances also the amino acid sequence, thanks to the excel- 

 lent work of the past few years. The amino acid code has been 

 published, at least in the newspapers. So let us reconstruct the 

 messenger coding for a given protein. This scheme was the more 

 inviting, since the determination of the nucleotide sequence of an 

 RNA by direct means is beset with very great difficulties. 



