Francis Crick : biography
Crick did tentatively attempt to perform some experiments on nucleotide base pairing, but he was more of a theoretical biologist than an experimental biologist. There was another near-discovery of the base pairing rules in early 1952. Crick had started to think about interactions between the bases. He asked John Griffith to try to calculate attractive interactions between the DNA bases from chemical principles and quantum mechanics. Griffith’s best guess was that A:T and G:C were attractive pairs. At that time, Crick was not aware of Chargaff’s rules and he made little of Griffith’s calculations, although it did start him thinking about complementary replication. Identification of the correct base-pairing rules (A-T, G-C) was achieved by Watson "playing" with cardboard cut-out models of the nucleotide bases, much in the manner that Linus Pauling had discovered the protein alpha helix a few years earlier. The Watson and Crick discovery of the DNA double helix structure was made possible by their willingness to combine theory, modeling and experimental results (albeit mostly done by others) to achieve their goal.
The DNA double helix structure proposed by Watson and Crick was based upon "Watson-Crick" bonds between the four bases most frequently found in DNA (A, C, T, G) and RNA (A, C, U, G). However, later research showed that triple-stranded, quadruple-stranded and other more complex DNA molecular structures required Hoogsteen base pairing. In addition, the entire field of synthetic biology began with researchers such as Erik T. Kool, where bases other than A, C, T and G are used in a synthetic DNA. In addition to synthetic DNA there are also attempts to construct synthetic codons, synthetic endonucleases, synthetic proteins and synthetic zinc fingers. Using synthetic DNA, instead of there being 43 codons, if there are n new bases there could be as many as n3 codons. Research is currently being done to see if codons can be expanded to more than 3 bases. These new codons can code for new amino acids. These synthetic molecules can be used not only in medicine, but in creation of new materials.Matthew Simon, "Emergent Computation: emphasizing bioinformatics," Springer, 2005
The discovery was made on 28 February 1953; the first Watson/Crick paper appeared in Nature on 25 April 1953. Sir Lawrence Bragg, the director of the Cavendish Laboratory, where Watson and Crick worked, gave a talk at Guy’s Hospital Medical School in London on Thursday 14 May 1953 which resulted in an article by Ritchie Calder in The News Chronicle of London, on Friday 15 May 1953, entitled "Why You Are You. Nearer Secret of Life." The news reached readers of The New York Times the next day; Victor K. McElheny, in researching his biography, "Watson and DNA: Making a Scientific Revolution", found a clipping of a six-paragraph New York Times article written from London and dated 16 May 1953 with the headline "Form of `Life Unit’ in Cell Is Scanned." The article ran in an early edition and was then pulled to make space for news deemed more important. (The New York Times subsequently ran a longer article on 12 June 1953). The Cambridge University undergraduate newspaper Varsity also ran its own short article on the discovery on Saturday 30 May 1953. Bragg’s original announcement of the discovery at a Solvay conference on proteins in Belgium on 8 April 1953 went unreported by the British press.
In a seven-page, handwritten letterhttp://news.msn.com/science-technology/letter-from-dna-discoverer-to-young-son-to-be-auctioned to his son at a British boarding school on 19 March 1953 Crick explained his discovery, beginning the letter "My Dear Michael, Jim Watson and I have probably made a most important discovery…".http://www.nytimes.com/interactive/2013/02/26/science/crick-letter-on-dna-discovery.html Crick letter transcribed at the New York Times The letter was put up for auction at Christie’s New York on 10 April 2013 with an estimate of $1 to $2 million, eventually selling for $6,059,750, the largest amount ever paid for a letter at auction.http://www.christies.com/about/press-center/releases/pressrelease.aspx?pressreleaseid=6195 Crick letter auction.
