Francis Crick (1916–2004)

It has often been asserted that the discovery of the structure of DNA in 1953 was the starting point for molecular biology. Whether or not this is true, it cannot be doubted that Francis Crick became a dominant figure in the early years of molecular biology. In those years there was a continual interaction between theory and experiment, in which Crick paid a leading role. I was in Cambridge at the time and on several occasions enjoyed the lucidity and clear thinking of his seminars, as well as his entertaining style. He was able to define an important problem and then indicate what the solution might be. Nothing better illustrates his remarkable abilities than a lecture on protein synthesis he delivered in 1957 to a Symposium organized by the Society for Experimental Biology, which I was privileged to attend. For the first time, he made it clear that there were only 20 primary amino acids in protein, so the coding problem became the mechanism by which the linear sequence of four Francis Crick DNA bases specified the sequence of 20 amino acids in proteins. He also suggested that there would have to be a series of intermediate adaptor molecules specific for each amino acid—a remarkable prediction of the brilliantly imaginative study by Crick, Barnett, Brenner and Watts-Tobin which ranks as a masterpiece of ge-existence of tRNA molecules with their three-base anti-codons. In addition, he expounded what he called the netic analysis. " In his book What Mad Pursuit, Crick recalls how he and Leslie Barnett first discovered that " central dogma " of molecular biology, namely, that information (by which he meant sequence information) could three closely linked addition (or deletion) mutations had a wild-type phenotype: " I looked across at Leslie. 'Do be transferred from nucleic acid to protein or from nucleic acid to nucleic acid, but not from protein to nucleic you realise,' I said, 'that you and I are the only people in the world who know it's a triplet code?' " When Crick acid or protein to protein. The central dogma was in fact a working hypothesis that has stood the test of time first proposed that these experiments should be done, his colleagues thought that the predictions were far too remarkably well, and those who thought that the discovery of reverse transcriptase contravened the dogma outlandish to be taken seriously, and that is why he …