delanceyplace.com 7/27/12 - jealousy and the double-helix

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In today's excerpt - in 1952, two young Cambridge researchers, James Watson of America and Francis Crick of Britain, unlocked the secret of the double-helix structure of genes. As with much in science and discovery, the process mixed hard-edged research with jealousy, personality clashes, hysteria, and competitive hubris:

"By the flip of a coin, our names in the original manuscript had the order Watson-Crick instead of Crick-Watson. So several Cambridge wags now could refer to our DNA model as the WC [water closet] structure. They suspected that our golden helix would be found tainted and destined for dumping down the water-closet drain.

"I had become monomaniacal about DNA only in 1951 when I had just turned 23 and as a postdoctoral fellow was temporarily in Naples attending a small May meeting on biologically important macromolecules. There I learned from a mid-thirtyish English physicist called Maurice Wilkins that DNA, if properly prepared, diffracts X-rays as if it were a highly organized crystal. The odds were thus good that DNA molecules (genes) themselves have highly regular structures that con­ceivably could be worked out over the next several years. ...

"Through the intervention of Salvador Luria, my Ph.D. super­visor at Indiana University, I was taken on five months later at the Cavendish Laboratory in Cambridge to work with an English chemist, John Kendrew. My ... career, however, would have likely soon aborted if Francis Crick had not been in the lab. From the moment I arrived, he treated me as if I was a much younger brother in need of help. Then 35 years old, Francis was effectively unknown outside Cambridge, having joined the unit only two years before. Already Francis's penchant for theory had made him a powerful addition to the team's protein-solving efforts. His first major success came soon after I arrived, when that October he helped work out the theory for diffraction from helical objects. Even so, Francis could not anticipate a long-term future within the unit, because the week before he had badly upset the head of the Cavendish Laboratory, Sir Lawrence Bragg, by arguing that he, not Bragg, first saw a potential new way of analyzing protein X-ray diffrac­tion patterns. To say the least, Bragg did not like the implication that he had pinched a younger colleague's idea. In fact, on that ill-fated Satur­day morning, Francis realized that neither his nor Bragg's precise approaches were that good and that only isomorphous replacement methods held out real hope.

"That fall of 1951 we had no reason to hope that we would be more than minor players in DNA research. The experimentalists at King's College London -- Maurice Wilkins and Rosalind Franklin -- were set to provide the definitive evidence for choosing one DNA model over another. But over the next year, their personalities clashed badly, and Maurice found himself driven away from X-ray analysis of DNA. Soon Rosalind had all the cards needed to solve the structure, provided she co-opted the model-building approach that Francis and I so passionately argued for. Here her greatest mistake was being put off by Francis's strong personal­ity that she thought masked a bumptious overextended intellect.

"Even less predictable was the inexplicable chemical botch that Linus Pauling, then universally perceived as the world's best chemist, made with his ill-conceived triple-stranded DNA helix. ... Quickly I raced into London to alert the King's group that Pauling's new helix was a botch and we should expect him quickly to devise a bet­ter model. Rosalind, however, thought I was being unnecessarily hyster­ical, telling me in no uncertain terms that DNA was not helical. Afterwards, in the safety of his office, Maurice -- bristling with anger at having been shackled now for almost two years by Rosalind's intransi­gence -- let loose the, until then, closely guarded King's secret that DNA existed in a para-crystalline (B) form as well as a crystalline (A) form. In his mind the cross-shaped B-diffraction pattern, shown on the X-ray he then impulsively took out of a drawer for me to see, had to arise from helical symmetry.

"Almost perversely, it was Linus Pauling's entry into the DNA game that made it possible for Francis and me to find the double helix. In November 1951, before it was clear that Pauling was out to get the DNA prize, Francis and I had been told by Sir Lawrence Bragg that DNA was off limits to the Cambridge unit because it belonged to the workers at King's. Even 14 months later, bad memories still existed of our awkward first attempts to build DNA models. But we then quickly gave up trying to guess the DNA structure and even passed details of the molds needed to build models to Maurice Wilkins. By now appraised of the B-form's existence, Bragg wanted Francis and me to have another go at building models. He hoped that our efforts -- possibly coordinated with those in London -- would generate the right answer before Pauling recovered his senses.

"No one then could have anticipated that in less than a month Francis and I alone would have found the answer and one so perfect that the experimental evidence in its favor from King's almost seemed an unnec­essary accompaniment to a graceful composition put together in heaven."