| Extras


Photo Finish

Associate Director John Haidar discusses the legacy of Photograph 51 and explains why it led to the discovery of the DNA double helix

It was the latest in a series taken by Rosalind Franklin and her PhD student, Ray Gosling, in the basement of the Biophysics Unit at King’s College London in May 1952. Described by the eminent physicist, J.D. Bernal, as ‘the most beautiful X-ray photograph of any substance ever taken’, this image captured, for the first time, the basic building blocks of every living thing. Before this, scientists had been using the term, ‘gene’, as a codeword for the smallest unit of genetic information passed down from one generation to the next. In fact, they had no idea what one looked like or, consequently, how it did its job. As a result, the significance of Photograph 51 in the story of genetics is incomparable, a catalyst for countless advances in biology, medicine, and paleontology for over half a century.

view of scientific slide through microscope
This is Photograph 51. From a series taken by Rosalind Franklin and her PhD student, Ray Gosling, in the basement of the Biophysics Unit at King’s College London in May 1952. Photograph © King’s College London Archives

In biology, function follows structure; that structure dictates function. In pursuit of the structure of DNA – a molecule too small to decipher using regular photography – Franklin and Gosling used a technique called X-ray diffraction. A fibre of DNA was fixed to a support, sealed in a camera in front of a piece of photographic film, and bombarded with X-rays. It was a process that required meticulous patience and skill: Franklin ran exposures for over 100 hours, constantly bubbling in hydrogen gas to control humidity and performing all of her calculations by hand. (Nowadays, scientists take thousands of images from different angles and digitally build up a three-dimensional image of the structure.) Conversely, Francis Crick and James Watson did none of their own experimentation, instead creating cardboard models with each new piece of information they gathered from data being collected by others within the scientific community. 

Within such a camera, as in a microscopic pinball machine, X-rays ricochet off molecular structures in their path and diffract, or scatter, in different directions. As they exit the molecule, the X-rays leave behind a pattern on the photographic film, which, when developed, reveals itself to the photographer. When Maurice Wilkins showed Watson Photograph 51, of the hydrated ‘B’ form of DNA, the 23-year-old American’s theory that the structure was a helix, an extended spiralling chain, was confirmed. The laws of physics assert that X-rays moving through any helical shape must scatter at a 90-degree angle to the helix, creating an ‘X’ shape, as seen here. Watson immediately recognised this telltale sign, famously doodling it in the margin of his newspaper on the 50-mile train journey back to Cambridge.

Above, below, and either side of the ‘X’ are four distinctly defined white diamonds. These show us that the central ‘X’ repeats, since we can see the halves of other ‘X’ structures to the left and the right, which are different DNA helices. The diamonds above and below the central ‘X’ are narrower, suggesting the strand is continuous. Finally, the two arms of the central ‘X’ are checkered at regular intervals, meaning that they appear as a series of dark blotches emanating from its centre. By analysing the placement of the blotches in addition to the distance of the DNA fibre from the photographic film, Crick and Watson were able to determine the structure of the molecule and, crucially, its function. These evenly-spaced markings correspond to pairs of bases – either adenine with thymine or cytosine with guanine – and indicate that DNA regularly twists in a kind of spiral staircase, in which the bases form the stairs.

If we look closely, there are ten blotches on each arm of the central ‘X’ before we reach the blurred area on the vertical axis, meaning there are ten pairs of bases stacked on top of each other in each turn of the helix. In fact, one of the blotches is missing – the fourth if you count out from the centre. This occurs when two strands, a so-called ‘double helix’, cross each other, at which point diffracted X-rays cancel each other out on the photographic film. This was (literally) a missing piece of the puzzle, a vanishing point that escaped Rosalind Franklin. Having taken Photograph 51, she didn’t turn her attention to it until the following year, deciding instead to focus on the less hydrated ‘A’ form of DNA. By that time, Crick and Watson were about to make the invisible visible via the discovery that would yield the secret of life.

The Dark Lady Of DNA

Brenda Maddox’s biography of Rosalind Franklin paints a vivid portrait of a remarkable woman dedicated to her life’s work – as revealed in these extracts 

black and white photograph of a scientist looking through a microscope
Collated excerpts taken from Rosalind Franklin: The Dark Lady of DNA by Brenda Maddox (Harper Perennial)

At the age of six, Rosalind Franklin’s aunt described her as ‘alarmingly clever’. The phrase has a modern resonance inaudible in 1926.

Having been a sickly child, the bracing air of the Channel coast was the reason for sending Rosalind to boarding school. Her dispatch from the family nest coincided with the birth of the Franklins’ fifth child, Jenifer. Poignant letters show Rosalind would have liked the pleasure of watching her sister grow up and that she longed for home, but accepted exile with the brisk alertness she brought to life with three brothers. Driven in on herself, she used her intelligence not to show emotion.

‘All her life, Rosalind knew exactly where she was going,’ according to her mother, ‘and at the age of 16, she took science for her subject.’ That she should have been so clear in her intention suggests that, by the age of 16, Rosalind realised what Albert Einstein gradually learned about himself: a scientist makes science, ‘the pivot of his emotional life, in order to find peace and security which he can’t find in the narrow whirlpool of personal experience’. Einstein offered this analysis in 1918 celebrating the award of a Nobel Prize to Max Planck. He proceeded to describe scientific research as, ‘akin to that of the religious worshipper or lover; daily effort comes from no deliberate intention or programme, but straight from the heart’. After entering Newnham College, Cambridge, Rosalind wrote at the top of the first page of her notebook, ‘What is a crystal?’ Getting ever deeper into crystallography, she joined the small band of the human race for whom these infinitesimal specks of matter were as real and solid as billiard balls.

Nevertheless, Rosalind’s interest in nothing but science concerned her father, Ellis Franklin, who believed it had taken the place of her religious belief. She sent him a declaration: ‘Science and everyday life cannot and should not be separated. I agree that faith is essential to success in life, but I do not accept your definition of faith. In my view, all that is necessary is the belief that by doing our best we come nearer to success and that success in our aims – improvement of the lot of mankind – is worth attaining.’ This humanistic credo came close to a renunciation of her Jewish faith. But, according to her sister, Rosalind was ‘always consciously a Jew’, a proponent of loyalty to family, belief in the importance of knowledge, and the virtue of hard work.

Cambridge, in spite of the war, did almost everything for her that a good university should. It changed her life, giving her both a profession and a personal philosophy. What three years at Cambridge did not do was end an astonishing ignorance about sex. Rosalind confessed to her cousin, Irene Franklin, she had never been kissed. The talk turned to having babies. The cousins discovered that, although each knew how a baby was born, neither knew how the ovum was fertilised. (A few months later, Irene informed Rosalind her fiancé had enlightened her. Rosalind was wiser too. She had asked a medical student.) But such things were remote from her mind.

The post-war world saw the admission of the first women to the Royal Society – for three centuries the citadel of the British scientific elite – 43 years since the Society threw out the nomination of the first to be proposed on the grounds that, as a married woman she was not a legal person and, hence, could not be a Fellow. The first half of twentieth-century science had belonged to physics, with the theory of relativity, quantum mechanics and nuclear fission. The second half of it would belong to biology. The secret of the gene – how our hereditary characteristics pass from one generation to another – was the hottest topic in science. That is where things stood when Rosalind arrived at King’s College London, on 5 January 1951.

A photograph taken on 2 May 1952 showed a stark ‘X’ of black stripes radiating from its centre. It was the clearest X-ray picture ever taken of a ‘B’ form of DNA. Rosalind numbered it ‘Photograph 51’ and put it aside, to return to the puzzle of the ‘A’ form. She had every reason to continue interpreting patterns, but refused to verify a helix without gathering more proof. Everything in her education had taught her to be absolutely sure of her facts before presenting them to the world. This lack of intuition would prove to be her Achilles heel. Scientific discovery is not creativity in the sense artistic composition is. ‘Science differs from other realms of human endeavour,’ explains Walter Gratzer [Emeritus Professor in Biophysical Chemistry at King’s College], ‘in that its substance does not derive from the activity of those who practice it.’ If Beethoven had not written his Ninth Symphony, no one would have done. However, if Watson and Crick had not discovered the double helix of DNA, others would have found it, and probably not long after.

‘Concerning Rosalind,’ Maurice Wilkins wrote to James Watson in 1966, ‘is there any mention in your book that she died?’ The book was The Double Helix, Watson’s candid account of the discovery. She is ‘Rosy’, the termagant who hoarded data she could not comprehend. As the decades have gone by, Watson has been forced to consistently defend himself against its publication. This unease may derive from his use of Rosalind’s experimental data behind her back, never telling her openly, even in the subsequent years of knowing her. Neither did Francis Crick. A footnote to a 1954 paper reads: ‘Information was kindly reported to us prior to publication by Drs. Wilkins and Franklin. We are heavily indebted in this respect to the King’s College group. Without this data, the formulation of our picture would have been unlikely, if not impossible.’

Rosalind Franklin did not have her eyes on the Nobel Prize. Nor did she worry about having been outrun in a race that no one but Watson and Crick knew they were running. She died proud of her international reputation both in coal studies and virus research, and of her list of published papers that would do credit to any scientific career, let alone one that ended at the age of 37. Rosalind knew her worth. With the prospect of going on to further significant achievement and, possibly, personal happiness, she was cheated of the only thing she wanted: the chance to complete her work. The lost prize was life.

The Building blocks of life by Christopher Oram

Capturing both the post-war conservatism of the time as well as the sense of discovery, set designer Christopher Oram talks about the real-life inspiration behind his re-imagining of Rosalind’s world

One of the great joys of being a stage designer is the opportunity it affords to research and learn new subjects with each job one undertakes, and the story behind the discovery of DNA proved to be no exception.

black and white photograph of Kings College London
Kings College London. Photograph © King’s College London Archives

The laboratories where Rosalind Franklin pursued her work when she returned to London from Paris were located beneath the quad in the King’s College campus next to Somerset House on the Strand. The building had been extensively damaged during the war, and so the labs were being newly constructed at the time she conducted her research. With an eye to dramatic timing, the laboratories are currently being relocated and the site redeveloped, as revealed in a recent visit. But amongst the photographs of the site in the archives there were several evocative black and white images showing the quad and the extensive bomb damage it received in wartime. The photographs show the surrounding buildings relatively unscathed though still coated in years of soot and grime from the pre-clean-air London smog, but in the centre of the pictures the ground is ripped open and the vaulted brick arches that supported the floor of the quad stand exposed like the ribs of a wounded animal.

A conversation with one of the physicists there confirmed my previous research, that generally the laboratories are preferred to be located underground where external stimulation is minimised, and atmospheric conditions kept stabilised. The irony of the exposed lower levels of the building in the photographs was not lost on me. The piles of brick rubble, the building blocks of the destroyed architecture, resonated in my mind with the research team’s search for the very building blocks of life itself.

Another element that had struck me on my recent visit to the site was the imposing sense of masculinity of the surrounding buildings, their classicism, the rigour of the repeated lines of windows, both arched and rectangular, the relative lack of detail. All these elements made me acutely aware of how Rosalind might have felt as she arrived from the relative freedom of post-war Paris to the more conservative world of British post-war academia. 

The play is about singular ambition, the taking of a photograph, and the discovery it inspires. Although the personalities involved were complex, and the relationships often fractious – and it is set against a background of post-war sexism, scientific elitism, and intellectual snobbery – I felt that I wanted to represent the extraordinary achievement of the team in the design as well.

The actual playing area, Rosalind’s laboratory, became situated at its centre, in the semi-destroyed vaulted brick arches of the rubble of post-war London. But if the surround represented the world in which Rosalind was working, then the floor of the set itself would represent the extraordinary discovery. And so it becomes an entirely under-lit Perspex-tiled floor, so that the space can glow like a photographic lightbox, representing the discoveries made there that would go on to build the entirely new and scientifically advanced world.