Editing George Gamow (section)

== DNA and RNA ==
In 1953, [[Francis Crick]], [[James Watson]], [[Maurice Wilkins]] and [[Rosalind Franklin]] discovered the [[Nucleic acid double helix|double helix]] structure of the [[DNA]] macromolecule. Gamow attempted to solve the problem of how the ordering of four different bases ([[adenine]], [[cytosine]], [[thymine]] and [[guanine]]) in DNA chains might control the synthesis of proteins from their constituent amino acids.<ref>{{Cite journal|last=Segrè|first=Gino|title=The Big Bang and the genetic code|journal=Nature|volume=404|issue=6777|page=437|date=2000-03-30|quote=the first serious theories of both these key ideas were formulated by the same man, a colourful, irresistibly playful physicist named George Gamow. |doi=10.1038/35006517|pmid=10761891|s2cid=205005362|doi-access=free}}</ref> Crick has said that Gamow's suggestions helped him in his own thinking about the problem.<ref>{{cite web|title=DNA: An "Amateur" Makes a Real Contribution|website=[[Library of Congress]]|url=https://www.loc.gov/exhibits/treasures/trr115.html|access-date=2007-07-11}}</ref> As related by Crick,<ref>Crick, Francis "What Mad Pursuit" (Basic Books 1998), Chap.8 The Genetic Code</ref> Gamow observed that the 4<sup>3</sup> = 64 possible [[permutation]]s of the four DNA bases, taken three at a time, would be reduced to 20 distinct [[combination]]s if the order was irrelevant.<ref>The twenty distinct combinations are:(3A)(3C)(3G)(3T),(ACG)(ACT)(AGT)(CGT),(2A,C)(2A,G)(2A,T)(2C,A)(2C,G)(2C,T)(2G,A)(2G,C)(2G,T)(2T,A)(2T,C)(2T,G).</ref> Gamow proposed that these 20 combinations might code for the twenty amino acids which, he suggested, might well be the sole constituents of all proteins. Gamow's contribution to solving the problem of genetic coding gave rise to important models of [[Degeneracy (biology)|biological degeneracy]].<ref>{{cite journal |last=Mason |first=P. H. |year=2010 |title=Degeneracy at multiple levels of complexity |journal=Biological Theory |volume=5 |issue=3 |pages=277–288 |doi=10.1162/BIOT_a_00041 |s2cid=83846240 }}</ref><ref>{{cite journal |last=Mason |first=P. H. |year=2014 |title=Degeneracy: Demystifying and destigmatizing a core concept in systems biology |journal=Complexity |volume=20 |issue=3 |pages=12–21 |doi=10.1002/cplx.21534 }}</ref>

{{anchor|Diamond code}}The specific system that Gamow was proposing (called "Gamow's diamonds") proved to be incorrect. 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 also [[Degeneracy of the genetic code|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.

In 1954, Gamow and Watson co-founded the [[RNA Tie Club]]. This was a discussion group of leading scientists concerned with the problem of the genetic code, which counted among its members the physicists [[Edward Teller]] and [[Richard Feynman]]. In his autobiographical writings, Watson later acknowledged the great importance of Gamow's insightful initiative. However, this did not prevent him from describing this colorful personality as a "zany", card-trick playing, limerick-singing, booze-swilling, practical–joking "giant imp".<ref>{{Cite book|last=Watson|first=J. D.|date=2002|title=Genes, Girls, and Gamow: After the Double Helix|location=New York|publisher=Random House|isbn=978-0-375-41283-7|oclc=47716375|url=https://archive.org/details/genesgirlsgamowa00wats}}</ref>