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In April 1953 *Nature* printed three papers on the structure of DNA, one after another: by James Watson and Francis Crick, by Maurice Wilkins and colleagues, and by Rosalind Franklin and Raymond Gosling (Watson and Crick; Wilkins, Stokes and Wilson; Franklin and Gosling). The story most people know is that Watson saw Franklin's "Photo 51" without her permission and solved the structure. Historians who went back to her notes say the real story is different, and more interesting.
What did Franklin work on?
Most of this section follows a 2023 *Nature* article by Matthew Cobb and Nathaniel Comfort, who are writing biographies of Watson and Crick and studied Franklin's archive at Churchill College, Cambridge (Cobb and Comfort, Nature, 2023).
Franklin joined the Medical Research Council-funded biophysics unit at King's College London in 1951. She had been using X-ray diffraction to study the structure of coal in Paris. Wilkins had found earlier that DNA could take two forms: what Franklin called the crystalline A form and the "paracrystalline" B form. Franklin found that raising the humidity turned A into B, and lowering it turned B back into A. Cobb and Comfort credit her with clearly differentiating the two forms.
The A form gave sharp, detailed diffraction patterns, more data but harder to analyse. The B form gave blurrier, simpler patterns. Franklin focused on the A form; from a chemist's perspective, Cobb and Comfort write, that choice was "perfectly logical".
What is Photo 51, and how much did it matter?
Photograph 51 is a particularly clear X-ray diffraction image of the B form taken by Franklin and her graduate student Raymond Gosling. In early 1953, about eight months after it was taken, Wilkins showed it to Watson. Gosling, by then supervised by Wilkins, had given him the photograph; he says he did so with Franklin's knowledge.
Cobb and Comfort argue that the photograph played little, if any, part in how Watson and Crick reached the structure: "everyone, even Watson, knew it was impossible to deduce any precise structure from a single photograph." Other data mattered more, including an informal report on the King's MRC unit that included Franklin's contribution. It confirmed a repeat of 34 ångströms in the B form, showed that DNA's unit cell was huge, and gave a "C2" symmetry for the A form, which implied an even number of strands running in opposite directions. Watson and Crick reached their model through six weeks of what they called "trial and error", with chemical calculations and cardboard models, then used the King's data, without permission, to confirm it.
By late February 1953, Franklin's notes show she had accepted that the A form was probably helical with two strands, and had realised that the order of bases did not affect the overall structure, so "an infinite variety of nucleotide sequences would be possible to explain the biological specificity of DNA." Cobb and Comfort conclude that she "was an equal contributor to solving it".
Why didn't she share the Nobel Prize?
The 1962 Nobel Prize in Physiology or Medicine went to Crick, Watson and Wilkins "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material" (Nobel Prize, 1962 summary). Franklin had died of ovarian cancer in 1958, aged 37. Since 1974 the Nobel Foundation's statutes have ruled out posthumous prizes unless death occurs after the announcement, and before 1974 a prize had been awarded posthumously only twice (Nobel Prize facts).
What can students learn from how she worked?
Cobb and Comfort note she was working on her own without a peer to swap ideas with, and was excluded from the informal exchanges Watson and Crick relied on. Three habits follow for a lab, a project or an olympiad problem.
Separate your data from your model. Write what the measurement shows ("a 34 Å repeat") apart from what you think it means ("a helix"). Check every model against all of the data, not the one striking result.
Ask what else could explain it. Before trusting one graph or image, list another structure or cause that could produce the same pattern.
Talk your work through with someone. Explaining your reasoning to a peer catches errors early. Our guide to running a study group that helps shows how to do this without it turning into chat.
For parents of daughters interested in science, Franklin is a role model, but the most useful message is not "she was wronged". It is that her careful measurement was central to one of the century's great discoveries. Our guide to girls' confidence in maths and physics has practical ways to back that up at home.
If the DNA chapter in NCERT biology still feels like a list of facts, the Fermi Concept Library gives every concept in biology and chemistry its own lesson and its place in the map, so you can see how structure connects to function.
Next time you see a single dramatic result, ask Franklin's question: what do the measurements actually show?
