It was how Rosalind Franklin was let down

The DNA of Rosalind Franklin: 70 years after the discovery of the structure of the molecule, a memoir by Maurice Franklin and James D. Bernal

Seventy years on from the discovery of the structure of DNA, controversy still surrounds two central points: how much credit Rosalind Franklin deserved, and the degree to which she was denied it. A lot of what we know about Franklin’s contribution comes from other people. In the early days, these were Franklin’s main partners: biophysicist Maurice Wilkins, and a few other people. Each of them gave interviews to journalists and researchers. Franklin, a physical chemist, left no comparable account: she died from ovarian cancer in 1958 at the age of 37.

Because of Watson’s narrative, people have made a fetish of Photograph 51. It has become the emblem of both Franklin’s achievement and her mistreatment.

This is an important point made by the journalist who drew on Franklin’s personal correspondence for her biography. Franklin was unhappy with the atmosphere at King’s College London and wanted to leave but didn’t have the time. Franklin was happier in London than in King’s, because she was an enthusiastic collaborators and mentor, according to crystallographer J.D. Bernal.

Franklin had confirmed the 34 result for the B form in her contribution. She reported that the repeating unit of the crystal of the DNA was huge and had a bigger number of atoms than any other unit cell. Key crystallographic data was added by Franklin which implied that there were even number of sugar-phosphate strands in the A form, and that the molecule had a C2 symmetry.

Oswald and his colleagues showed in 1944 that DNA could turn benign Streptococcus pneumoniae into a strain that could cause death. But it remained far from clear that it was the genetic material in all organisms.

A group of biophysicists funded by the Medical Research Council at King’s College London were using X-ray tools to study the structure of the atom. They were joined by Franklin who was researching the structure of coal at the Central State Laboratory of Chemical Services in Paris.

With the Signer DNA, Franklin was able to exploit a discovery that Wilkins had made earlier — DNA in solution could take two forms, what she called the crystalline or A form, and the paracrystalline or B form. Franklin found that she could convert A into B if she raised the relative humidity in the specimen chamber.

Franklin didn’t think that a single base could bond only with two others, creating an exact replica of the molecule. She could not have made a model that was satisfactory if she had tried the correct forms of the bases. She didn’t realize her data implied that the two strands were different in orientation and that the B form was the biologically functional form. (The A form is found only under laboratory conditions.) She didn’t have time to make the final leaps, because they were lost to the answer.

They did not steal the data from the King’s group but they made the structure of DNA from it. Instead, they solved the structure through their own iterative approach and then used the King’s data — without permission — to confirm it.

The C2 symmetry was one of 230 types of crystallographic 3D ‘space groups’ that had been established by the end of the nineteenth century. Franklin didn’t appreciate its significance because she wasn’t familiar with it. Franklin said she could have kicked herself if she had known the structural implications. Crick did realize the implications because he happened to have studied C2 symmetry intensely. But even he did not use Franklin’s determination of this symmetry when building the model; rather, it provided a powerful corroboration when their model was complete.

After Watson and Crick had read the MRC report, they could not unsee it. They should have made it clear to Franklin and Wilkins, and also to the rest of the world, that they’d used the data and then published their work.