The story of the discovery of the DNA double helix that has been accepted as true for more than fifty years is wrong, according to previously unpublished documents analyzed by biologist Matthew Cobb and historian Nathaniel Comfort.

Contrary to what has been said so far, it is not true that James Watson and Francis Crick discovered the double helix because they knew how to interpret a photo of DNA that Rosalind Franklin had obtained but had not been able to decipher. It is also not true that Watson and Crick appropriated Franklin’s data and deprived her of the credit she deserved.

According to Cobb and Comfort, who advanced their findings yesterday in Nature to coincide with the 70th anniversary of the publication of the discovery of the double helix, “Franklin was an equal member of a group of four scientists working on the structure of the DNA”.

The other three – Watson, Crick and Maurice Wilkins – received the Nobel Prize in Medicine in 1962 for the discovery. Rosalind Franklin, who had died in 1958 at the age of 37 from ovarian cancer, could not be awarded.

The relations of Watson and Wilkins with Franklin, the only woman of the four, were not good. But they shared data in accordance with the scientific culture of the time.

Cobb and Comfort, who are working on biographies of Watson and Crick to be published in 2025, came to these conclusions after studying the notes Rosalind Franklin took on her research, kept at Cambridge University . They have also analyzed a report with the results of Franklin’s experiments that Max Perutz, Crick’s boss, received during a visit to the institution where she worked. And they found a report on the story of the discovery that Time magazine commissioned but never got around to publishing.

These documents show that things did not happen as James Watson described them in his book The Double Helix, published in 1968, which has fueled subsequent erroneous accounts of the discovery of the structure of DNA.

A key episode in these stories is the iconic Photograph 51 taken by Rosalind Franklin and PhD student Raymond Goslin. It is an image of DNA observed with X-ray diffraction. According to Watson’s version, he went to visit Franklin at King’s College in London in early 1953 and they argued. Maurice Wilkins, who also worked at King’s College, showed him that same day Photograph 51 that Franklin and Goslin had obtained eight months earlier.

He says he immediately realized that only a helix structure could produce that image. But it is “an absurd presumption […] that Franklin, the qualified chemist, could not understand his own data, and that he, a beginner in crystallography, understood it immediately”, note Cobb and Comfort. “Furthermore, everyone, even Watson, knew that it was impossible to deduce any precise structure from a single photograph.”

What allowed Watson and Crick to decipher the structure of the double helix was their work with cardboard models in an office at Cambridge University. Watson and Crick made the models reasoning as theoreticians and checked whether they were on track using the experimental data obtained by Franklin and Wilkins.

The key data was not in Photograph 51 but in the report that Max Perutz, Crick’s boss, had received on his visit to King’s College. Although Watson and Crick used the data without permission, Franklin knew they had it.

In that report, Franklin already pointed out that the bends of the DNA helices were separated by a distance of 34 angstroms, that the molecule had an enormous amount of atoms and that it had a type of symmetry called C2. Crick was an expert in this kind of symmetry

Finally, Watson, Crick, Franklin and Wilkins presented their results in three papers published in Nature on April 25, 1953. The most important of the three, which described the DNA double helix and changed the history of biology and medicine, was signed solely by Watson and Crick without any mention of the contributions of Franklin and Wilkins.

In a paper published the following year, Watson and Crick acknowledged that, without Franklin’s data, “the formulation of our structure would have been very improbable, if not impossible.”

“Rosalind Franklin has been reduced to the ‘offended heroine’ of the double helix. She deserves to be remembered, not as the victim of the double helix, but as a researcher who contributed equally to solving its structure”, state Cobb and Comfort in Nature, who point out that “neither Franklin nor Wilkins ever questioned how the structure” of DNA had been discovered.

As for the other protagonists, “Francis Crick is a more respected figure today than James Watson”, declares Nathaniel Comfort by email. “Watson’s reputation is as negative as it was positive at the time. This is largely due to his own actions, especially his repeated comments about the genetics of races and intelligence.”