George Gamow - DNA and RNA

DNA and RNA

After the discovery of the structure of DNA in 1953 by Francis Crick and James D. Watson, Gamow attempted to solve the problem of how the order of the four different kinds of bases (adenine, cytosine, thymine and guanine) in DNA chains could control the synthesis of proteins from amino acids. Crick has said that Gamow's suggestions helped him in his own thinking about the problem. As related by Crick, Gamow suggested that the twenty combinations of four DNA bases taken three at a time correspond to twenty amino acids used to form proteins. This led Crick and Watson to enumerate the twenty amino acids which are common to most proteins.

However the specific system proposed by Gamow (known as "Gamow's diamonds") was incorrect, as the triplets were supposed to be overlapping (so that in the sequence GGAC (for example), GGA could produce one amino acid and GAC another) and non-degenerate (meaning that each amino acid would correspond to one combination of three bases - in any order). Later protein sequencing work proved that this could not be the case; the true genetic code is non-overlapping and degenerate, and changing the order of a combination of bases does change the amino acid.

After 1954 Gamow was involved in the RNA Tie Club, a discussion group of leading scientists concerned with the problem of the genetic code. One of Gamow's colleagues in the Club was Nobel prize winner James D. Watson, co-discoverer of DNA, who acknowledges Gamow in his own autobiographical writings.