DNA ‘A’ and ‘B’ forms
Collaborate? She exploded. It was the only time that Wilkins saw her completely lose control. ‘How dare you interpret my data for me!’ Rosalind had good reason. Her work was her life, the core of her identity. Undervalued at King’s, she had just achieved extraordinary results by working in virtual isolation. Now what she saw as a less able colleague of higher rank was proposing to elbow in and spoil the clarity of her investigation.
Where Wilkins saw rage, one of her brothers saw despair. One night when Colin Franklin and his wife Charlotte were expecting Rosalind to dinner at their home in Hampstead, he was startled to see her arrive in tears — ‘weeping’ as he recalled, ‘beyond redemption’. In the Franklin manner, he pretended not to notice and said nothing.
By late October Rosalind was so miserable that she was ready to abandon her work. She poured her heart out to her old friend and confidante, Adrienne Weill.
Dear Adrienne,
I’m sorry I have been silent so long. I came back from my holiday to the blackest of crises in the lab, which lasted weeks and weeks, took all my energy and left me too fed up to write to anybody. Things have calmed down a little now, but I still want to get out as soon as possible, and think seriously of coming back to Paris if Paris will have me.
On 25 October 1951, with ‘one more heave’, the Conservatives ousted Labour in the general election and were back in power, with Winston Churchill prime minister once again. At almost the same time, Randall was forced to recognise the contest within his own borders. He called Wilkins and Rosalind to his office, for a meeting from which a treaty of sorts emerged. Rosalind, using the Signer DNA, would concentrate on the A form. Wilkins would tackle the B. From then on communications between the two virtually ceased.
Far from settling the matter, the formal division of labour made things worse, for as Rosalind took all the Signer DNA with her, plus the Phillips micro-camera, Wilkins was left with the pig thymus DNA supplied by Chargaff, and older equipment. Worse luck, the Chargaff DNA did not crystallise, presumably because of its low molecular weight, and Wilkins was thus unable to duplicate the A-B transition.
Wilkins had made a bad deal. The deal was bad for Gosling too. A PhD candidate, he found himself torn between his thesis supervisor (Rosalind) and the assistant head of his department. He was left, in another of his colourful phrases, ‘acting as Envoy Extraordinary and diplomatically carrying the ‘‘sense’’ of messages between them’. Freda Ticehurst felt very sorry for him: ‘He got very down in spirits and worried whether he should continue working with Rosalind. But he never felt dislike for Rosalind, only sympathy.’
Why, the outsider must ask, was the Signer DNA so special? If DNA is the molecule of life and exists in every cell, why was one particular jam jar of it so prized? The answer is that the precipitate prepared by Rudolf Signer of Berne and handed out generously on a day in May 1950 had very special properties. Touched by a glass rod, the gel could be pulled out into long fibres, or strings. Wilkins had an apt comparison — ‘It’s just like snot!’
Fresh DNA was best obtained from animal organs. Researchers spent a lot of time at slaughterhouses and butcher’s shops (where calf thymus glands were sold as sweetbreads). As there was no proper refrigeration, the organs from freshly killed animals had to be obtained before degenerative changes started in the tissues.
The next task was to extract the DNA from the organs without degrading it, then to pull out from the viscous DNA solution a single oriented fibre, position it in front of a camera and to direct an X-ray beam through it. This produced spots on the film from which to try to work out the atomic position of the repeating units in the fibre.
Signer’s DNA, because of his careful and unique preparation with alcohol and salt, was superior to the rest because of its very high molecular weight. According to Paul Doty, a Harvard chemist and another lucky recipient of the manna from Berne,
In the early 1950s little was known about preparing DNA. Most attempts led to degraded material that could not be pulled into a fibre as was needed for X-ray diffraction. Signer’s preparations did produce good fibres. How he avoided substantial degradation was not clear at the time.
His recipe was vague and clearly did not describe the whole art. Hence his samples were much desired by those who knew they gave good diffraction diagrams.
At King’s, Mary Fraser, a chemist, took on the task of trying to make more DNA like Signer’s, using crates of cod roe. What she produced had a molecular weight lower than Signer’s but was satisfactory for making what was needed for the doctoral thesis of her husband Bruce Fraser, who was studying DNA through infrared methods. He recalled, ‘We ended up smelling like a couple of Billingsgate porters. There were no showers at King’s.’
After the dramatic division of labour, Rosalind threw herself into collecting and analysing her data. Her notebooks reflect intense activity: ‘Either the structure is a big helix or a smaller helix consisting of several chains. The phosphates are on the outside so that phosphate—phosphate inter-helical bonds are disrupted by water.’
It was obvious to see that the phosphates were on the outside because of the ease with which the water went in and out of the fibre with changes in humidity. Phosphates soak up water — ‘hydrophilic’ in her terminology — causing the DNA molecule to lengthen in the process.
Wilkins found isolation less conducive to productivity. Frustrated, he began visiting Cambridge regularly to talk with his old friend Francis Crick at the Cavendish. Crick, a protein crystallographer, had met Maurice while working for the Admiralty during the war, then in 1947 when, looking for a job, he wandered into the biophysics enterprise at King’s. He did not stay long. Interested in what he recognised as ‘the borderline between the living and the non-living’, he found the cod roe, ram sperm and calf thymus glands on the King’s research menu ‘rather far on the biological side ofthat border’.
The two men had much in common: both had been engaged in wartime weapons research, had a broken wartime marriage and first child behind them and were picking up the pieces of disrupted lives. And, yes, Crick too had been influenced by Schro dinger’s What Is Life?
In their mid-thirties they even looked somewhat alike — very tall, lean, bony-faced. They were equally adorned with two middle initials, which looked quite grand in scientific publications: F.H.C. Crick, M.H.F. Wilkins. There was one major difference: Crick had remarried, and had a pretty French wife of artistic bent. Indeed, the Crick household in Cambridge, with a racy bohemian atmosphere, good food and scientific conversation, was a magnet to Wilkins who, German girlfriend notwithstanding, was just this side of eccentric, locked in on himself, living in a small top-floor flat overlooking Tottenham Court Road and going about in a curious long black coat with the collar turned up. Needing companionship, hot dinners and conversation, he became overly close to Crick and attracted to his wife, Odile. Her French elegance, much noticed in austere Cambridge, was summed up by another admirer as: ‘she wore white dresses’.
But Crick had someone else to talk to. Jim Watson had arrived in Cambridge from Copenhagen, having wangled a transfer of his Merck—National Research Council fellowship from Copenhagen to Cambridge so that he could join Max Perutz’s department to study crystallography and plant viruses. Watson told his fellowship office in Washington baldly that he now knew that X-ray crystallography was the key to genetics. A symposium that summer at his own favourite conference venue, Cold Spring Harbor on Long Island, had brought home to him even more than ever that DNA was the carrier of genetic inheritance. What’s more, his mentor Max Delbrück had persuaded him that understanding the gene was the problem of the century. Whoever accomplished it would be covered with honour. Honour was what Watson wanted, and he headed for it in Room 103 of the Austin Wing of the Cavendish Laboratory. The small bare room contained only blackboards, tables and Francis Crick.
Affinity is no easier to explain than antipathy. The two men clicked just as much as Rosalind and
Maurice repelled each other. Both were irrepressible talkers, with quick minds and complementary expertise. Watson knew biology and genetics; Crick was a physicist who had taught himself X-ray crystallography. The words poured out and continued every day over lunch at the Cavendish’s local pub, The Eagle. Both laughed a great deal, even when, as was not always the case, they were discussing how genes might be put together — Crick in a loud bark, Watson in a snuffling snort that showed a lot of his gums. Crick had the merry, knowing eyes of the super-bright; Watson the horizon-scanning gaze of radar. Neither had an ounce of depression in him, while Rosalind and Maurice, in their very different ways, were prey to melancholy.
Nobody at the Cavendish was doing work on DNA. That belonged to King’s. Unlike Watson, who had snared his doctorate at the age of twenty-three, Crick at thirty-five had yet to get his. He was working on his thesis on X-ray diffraction of proteins. While not specifically interested in DNA itself, he was curious about how genes copied themselves. From Wilkins he was informed about the possibilities of a helical structure for DNA. Watson goaded him to follow Pauling’s lead and build a model. There was no need to spend any money or touch a fibre of the snot-like gel — just to make an educated guess of how the molecule might be put together according to the rules of chemistry. Then, with balls and wires from the machine shop, assemble a structure illustrating the guess in three dimensions.
Both men had been deeply impressed by Pauling’s achievement, as well as by the failure of their Cavendish colleagues to discover it themselves. They were impressed too by the method Pauling had used to succeed: model-building. However, Crick was on a precipice at the Cavendish. Bragg found him irritating, intrusive, over-confident and under-productive, and hoped he would finish his thesis and be gone. There was no way that Bragg would accept Crick’s diversion from his main task to speculations about DNA.
For Rosalind, Wilkins was not the only irritant at King’s. He had a sarcastic office mate, Bill Seeds, a rotund Irishman with Swiss connections on his mother’s side, who was a graduate of Trinity College Dublin and engaged on the mechanical details of a reflecting microscope. Seeds was the Biophysics Unit’s joker, given to raucous remarks. He also loved running round the department, stirring things up, and coining nicknames: the quiet thinker Stokes was the ‘Archangel Gabriel’; the lean and taciturn Maurice was ‘Uncle’; Honor Fell was ‘Aunty’. It did not take long for Seeds to turn Rosalind into ‘Rosy’. She could not stand him. He did not like her either.
She knew very well what the common diminutive of her name was — she had an Aunt Rosie — but she herself had long succeeded in being called ‘Ros-lind’, pronounced in two clipped syllables. From her family and close friends, she would accept ‘Ros’.
It might have helped if Rosalind had recognised that all at King’s had nicknames. To Dorothy Hodgkin’s biographer, Georgina Ferry, these had a double function: to demystify superiors but also to get round the stilted custom then prevailing in British offices, laboratories and public schools in which males addressed even their best friends by surname alone, while a woman’s surname was always prefaced by ‘Miss’ or ‘Mrs’.2
Rosalind and Seeds had a run-in over the design for her tilting camera stand. Seeds felt the design was poor; he did not want scarce workshop time wasted, so suggested some changes. Rosalind refused to discuss them. What he saw as her ‘That’s the way we did it in France and that’s the way that it’s going to be done here’ attitude brought out the worst in him. Once when she had covered some apparatus in the lab with blackout cloth, she came back to find the sign ‘Rosy’s Parlour’ hung on it. This hint of the gypsy, the alien and the occult shows the swart associations that Rosalind stirred at King’s.
The prank sent her into another tantrum and she called them all ‘little schoolboys’.
Early in November, Crick invited Wilkins to visit him at his home in Cambridge for the weekend and Wilkins talked freely. Watson was there too. They pumped Wilkins for information and he repeated much of what he had said at the Perutz meeting in July, interspersed with comments on what had become an obsession, his difficulties with Rosalind. She had, he felt, virtually shut him out of his own subject. She had been given the best cameras and best DNA, only to keep her results to herself instead of sharing them with her group in the spirit of scientific collegiality.
Wilkins had no reason not to talk freely. As far as he knew, nobody at the Cavendish was working on DNA. Watson and Crick kept urging him to follow Pauling’s example and build models. But Rosalind would not hear of it. There was no way to prove that any model — no matter how beguiling — reflected reality. Had she not heard Bernal say in Stockholm that any proposed molecular structure should be tested against the X-ray evidence? Such evidence was what she had been enlisted to find. Rods, metal plate, wires, coloured plastic balls, to her were pointless diversions, signifying nothing. The time to build models, she told Wilkins, was when you knew what the structure was.
Not everybody at King’s was opposed to model-building. In early November, Bruce Fraser, working for his doctorate with Dr William Price in the spectroscopy group (allied to the Biophysics Unit), decided to put together a model to summarise the latest DNA thinking. Fraser, who sported a black handlebar moustache testifying to his war service as a pilot for the RAF, was neutral in the Franklin-Wilkins feud. Such contact as he and his wife Mary had with Rosalind was entirely friendly. Rosalind discussed the model with him just as she had read Sven Furberg’s thesis on which it was based. When Fraser asked her to guess how many chains there might be in the molecule, she ventured three. Wilkins said the same, for the same reasons: the measurements of density and water content of DNA suggested more than one chain and probably three. Two would not be enough to fill the space. (As Linus Pauling later came up with a three-chain answer, the reasoning was sound, if erroneous.)
Fraser’s model of DNA, completed very quickly, was a simple structure that had what would turn out to be all main features correct except for the number of chains. It had a helical shape, phosphates on the outside, and bases stacked like a pile of pennies, separated by the 3.4 A distance worked out by Astbury. Rosalind saw it, and her view was what she felt about all models: ‘That’s very nice — how are you going to prove it is the solution?’
A big step in the right direction, Fraser’s November 1951 model was another glaring example of King’s’ institutional hesitancy. Its details were never published, just as Stokes’s calculations on helical diffraction were never published. Wilkins himself did not think it worth pursuing because, although Fraser’s model was full of potential, there was no structural hypothesis behind it; it did not explain anything. In a few months Bruce and Mary Fraser, with their new baby, prepared to emigrate to Australia — out of the drama until its very end.
On 21 November King’s held a colloquium on nucleic acid structure. There were three speakers, two of whom were barely speaking to each other. First, Wilkins repeated what he said in Cambridge in July. Next Stokes summed up his work on helical theory. Finally, Rosalind presented her findings about the A-to-B transition in hydrated DNA. The notes she made to prepare for the talk show much mention of the helical possibilities of DNA, but in the memories of those present, all admittedly vague, she did not utter the critical word ‘helix’ to which Wilkins and Stokes had just given so much attention.
None of the three speakers suggested any connection between form and function — that is, they did not anticipate that seeing the shape of the genetic molecule would reveal how it did its work.
If Rosalind could have known that her entrance on the world stage would be dominated by what she wore on 21 November 1951, would she have dressed differently? Almost certainly not. For her presentation she wore what she felt was appropriate for work: probably a white blouse, dark skirt and lab coat. Watching her intently from the small audience of fifteen or so was Jim Watson. He had asked Maurice if he might attend. He hoped to learn whether Rosalind’s new X-ray pictures might yield any support for a
helical DNA. Also, having heard about the terrible Rosy from Maurice, he was keen to get his first look.
Girls, for Watson, were equal to genes as objects of supreme curiosity. He appraised her against his standard of feminine beauty — Hedy Lamarr, the French ‘popsies’ studying English at Cambridge language schools, and his sister Elizabeth — and found her wanting. As he recorded in The Double Helix, in a sentence that has since become notorious: ‘Momentarily I wondered how she would look if she took off her glasses and did something novel with her hair.’
Believing that young women should add sparkle to life, Watson did not think much of Rosalind’s dress sense either:
Though her features were strong, she was not unattractive and might have been quite stunning had she taken even a mild interest in clothes. This she did not. There was never lipstick to contrast with her straight black hair, while [he added ungrammatically] at the age of thirty-one her dresses showed all the imagination of English blue-stocking adolescents.
Watson had no idea of Rosalind’s scientific reputation, let alone her background. An acute observer of physical detail but a poor psychologist, he assessed her as the ‘product of a mother whose own career aspirations had been thwarted’ and who ‘duly stressed the desirability of professional careers that could save bright girls from marriages to dull men’.
The very opposite was true. Rosalind had made herself into the antithesis of her mother. The last thing that Muriel Franklin wanted, for herself or her daughter, was a career, and, being married to a man she found the most fascinating in the world, she was incapable of imagining the plight of a woman chained to a bore.
Thus preoccupied, Watson did not grasp what Rosalind said about the water cloaking the phosphates on the outside of the molecule. He took no notes. He never did.
Rosalind Franklin Page 17