Francis Crick: Discoveror of the Genetic Code By Matt Ridley 213 pp. Atlas Books/HarperCollins, 2006.
“I have never seen Francis in a modest mood”, so begins the first line in James Watson’s account of the momentous discovery of The Double Helix for which he shared the Nobel prize with Francis Crick in 1962. Indeed the entire scientific life of Francis Crick is a tale of immodesty: first the structure of the DNA, then the genetic code and finally neuroscience and consciousness.
Yet, the beginning could hardly have been more different. Known in school as a moderately clever but distracted kid, Crick soon acquired a reputation for someone who just talked a lot – very loudly at that – and never managed to finish anything satisfactorily. His real scientific career started very late, when he was over 30 and the discovery of DNA structure came when he was 37.
The decisive influence that started and then continued to shape his scientific career seems to have been the presence of the other. All his major discoveries were made in partnerships with a partner who could serve as a sounding board for ideas. First was George Kriesel, an eccentric Austrian logician who specialised, among other things, in making random proposals to women on the Riviera, see Kreiselinana . From Kreisel, he learned how to organise his thoughts precisely and logically. Next was Watson with whom he developed an instant rapport. One of the best administrative decisions his bosses at Cambridge made was to put the two together into a room where they could talk loudly and endlessly. Then later it was Sydney Brenner with whom Crick cracked the genetic code and finally in the last 18 years, an unfulfilled quest for understanding consciousness with Christof Koch.
Crick’s approach to doing science is a great way to debunk common public parodies. The scientist is depicted as careful and stodgy, collecting fact after fact, and refusing to speculate wildly. Exactly the opposite of Crick! Time after time, Crick tossed up idea and hypotheses out of nowhere, with not an ounce of evidence in support. The best example of this is probably the paper “On Protein Synthesis” from 1957 in which he made a set of bold assertions each depending on one another: the function of genes is to make proteins, there are 20 kinds of amino acids in proteins, and all occur in nearly all proteins, whatever the species or organisms … all guesses, and all, as later turned out outrageously, correct! The most remarkable part of the paper were the two general principles Crick set forth:
My own thinking is based on two general principles, which I shall call the Sequence Hypothesis and the Central Dogma. The direct evidence for them both is negligible, but I have found them to be of great help in coming to grips with … very complex problems.
The “Sequence Hypothesis” states that a sequence of bases determines a amino acid and nothing else is needed to tell a protein how to fold. This was complete heresy at the time, later a fundamental surprise of molecular biology, but just standard bioinformatics today. The “Central Dogma” in original form was:
Once “information” has passed into protein, it cannot get out again … the transfer of information from nucleic acid to nucleic acid or from nucleic acid to protein may be possible, but the transfer from protein to protein or from protein to nucleic acid is impossible.
Today, this is again,a central tenet in molecular biology, namely that information passes uni directionally, from DNA to RNA to proteins.
The common parody of the fact-addicted cautious scientist fits much better, Rosalind Franklin , the crystallographer and contemporary at King’s College who had important data, but refused to speculate on it, possibly denying her a proper share of the discovery of the double helix.
There is a beautiful vignette for computer scientists, during a visit by Francois Jacob, one half of the great French team with Jacques Monod. Monod and Jacob had done some experiments that seemed to decisively refute Crick’s assertions about protein synthesis: when new genes were introduced, proteins were synthesised far too quickly for there to be time to build up new ribosomes as Crick’s theory seemed to require. During Jacob’s talk, suddenly Brenner let out a yelp and started talking very fast, and in response, so did Crick. They had seen the solution! And the solution came from Brenner recalling a paper he had studied several years ago by the great Hungarian mathematician John von Neumann on the design of self-reproducing automata. There von Neumann had laid out the basic principle of computer architecture: that the “tape” which held information or instructions was separate from the “tape reader” that interpreted or executed those instructions. This was precisely what the ribosomes were: they merely read the instructions carried to them by messenger RNA and executed them to synthesise the proteins!
On ecan’t but speculate that Crick would have loved to stay a bit longer as the field of Systems Biology takes shape and starts addressing some of the problems in neuroscience he was obssessed with at the end. In particular, his speculations on the claustrum and his highly connected structure sound straight out of recent network biology!
Finally, science funders have lessons to learn from the career of Francis Crick, especially the early days with Watson. Crick and Watson were commonly regarded as ignorant fools with no background in the area, meddling in things far beyond their ken, hoping futilely to compete with luminaries like Linus Pauling. They were constantly straying from their assigned tasks for which their positions were funded, and never did their reports etc on time. Thank God for science!
Matt Ridley has proved yet again, that he is much better at writing wonderful popular science books than at running banks.
