Today in History: Rosalind Franklin and the Discovery of DNA

On July 25, 1920 the English biophysicist Rosalind Franklin was born. She was instrumental in discovering the molecular structure of DNA, though her vital contributions were only posthumously acknowledged. After receiving her PhD from Cambridge in 1945 she worked as a research associate for John Randall at King's College in London. Beginning in early 1951 she took X-ray diffraction photographs of DNA that showed a helical form of the molecule, a finding confirmed by James Watson and Francis Crick who subsequently won the Nobel Prize for their DNA research. In lecture notes dated November 1951 (16 months before Watson and Crick published their description of DNA) Franklin wrote the following:

Conclusion: Big helix in several chains, phosphates on outside, phosphate-phosphate inter-helical bonds disrupted by water. Phosphate links available to proteins.

Her photographs clearly demonstrated that DNA was a double helix (see left), a finding that flatly contradicted the widespread theory that the structure had three chains (a view held by Watson and Crick at this time). However, unknown to her, John Randall had taken her unpublished results and presented them at a seminar. Her colleague at King's College, Maurice Wilkins (who was also working on the structure of DNA), then reported her findings to James Watson and Francis Crick. Two weeks later Watson and Crick built their now famous model of the DNA double helix.

As Brenda Maddox wrote in Nature in 2003 (pdf here):

She did not know that they had seen either her X-ray photograph, showing unmistakable evidence of a helical structure, or her precise measurements of the unit cell (the smallest repeating unit) of the DNA crystal. As Watson was to write candidly, "Rosy, of course, did not directly give us her data. For that matter, no one at King's realized they were in our hands."

Three months later, in February 1952, Franklin submitted her results to the journal Nature, where they were published on April 25, 1953 along with two other papers on the structure of DNA. Hers appeared third. The first was by Watson and Crick, the second by her colleague Wilkins with co-authors Stokes and Wilson, and the third by Franklin and Goslin (access all three papers here). Franklin went to her early death, of ovarian cancer in 1958, not knowing that her work had been crucial for the discoveries by Watson, Crick and Wilkins. On December 31, 1961 Francis Crick had sent a letter to Jacques Monod, reprinted in Nature Correspondence, in which he wrote that Franklin's work had been "the data we actually used." However, when the three scientists accepted their Nobel Prize in 1962 there was no mention of Franklin's contribution.

Fortunately, thanks to the work of historians and archivists, Rosalind Franklin's important contribution to the discovery of the double helix is becoming more widely known. During a time when women's achievements were downplayed and undermined, Franklin persevered and accomplished important work in her field. She was a scientist of the highest calibre, one who respected the scientific method as a penetrating tool and an inspiring vision for daily life. There is no better way to celebrate the day of her birth than by continuing to honor the method she devoted her life to.