Stephen Franklin, nephew of Rosalind Franklin, offers a personal account of his aunt's role in discovering the structure of DNA.
Rosalind Franklin 1920-1958
Dr Rosalind Franklin was a great scientist. She was also my aunt.
Sadly she died tragically young of cancer of the womb at the age of 38. As I was only four at the time, my memories of her are just of a few moments.
I do remember visiting her with my parents at her laboratory at Birkbeck, where she made us some tea on her Bunsen burner.
I always knew that she worked on DNA, but was unaware just how highly her work was regarded within her profession until I was on a ski holiday.
Staying in the same chalet as me was a professor of biochemistry. I mentioned that my late aunt was a biochemist called Rosalind Franklin.
He was extremely impressed and said to me that she deserved the Nobel prize more than Francis Crick, James Watson and Maurice Wilkins put together and it was tragic that it couldn't be given posthumously.
I found a similar reaction from a New Zealand biochemistry lecturer (whom I also met on a skiing holiday) only two years ago; so I decided to find out more.
Rosalind's interest in nucleic acids started early.
In late 1939, when Rosalind was a nineteen-year-old student at Newnham College, Cambridge, studying chemistry, she made a speculative sketch in her workbook of a form of nucleic acid.
Rosalind's biographer Brenda Maddox writes in 'The Dark Lady of DNA' that the form "represents a helical structure. She made a note to herself: 'Geometrical basis for inheritance?'"
Rosalind did her thesis on holes in coal and received a PhD from Cambridge in physical chemistry in 1945.
X-ray image expert
She worked very happily and successfully on X-ray diffraction of carbons in France until 1951, by which time she was one of the world's most capable practitioners of X-ray diffraction.
Her research had important industrial applications in the coal industry for decades afterwards.
When Rosalind moved to King's she was asked by her boss, JT Randall, to work on the structure of DNA and believed she had the X-ray work exclusively to
Unfortunately Wilkins believed she would be working together with him and did not know that she had been told otherwise. This led to a very unhappy working atmosphere at King's.
Meeting Watson and Crick
Early in her time at King's, Rosalind and Wilkins were invited to Cambridge to see a model of DNA made by Crick and Watson.
It was a three-chain helix and, as Rosalind pointed out, it included less than one tenth of the amount of water that DNA contained.
Rosalind obtained a far higher quality photo of DNA than anybody had achieved before and noticed that DNA changed its form when it became wet.
The transition was so abrupt that on one occasion the fibre fell off its holder.
She produced one extremely clear photo of DNA in its wet form (photo 51) that was unmistakably a helix.
As previously agreed with her boss (JT Randall) she put this down and worked on the dry form.
She worked through a very thorough but slow analysis of the dry DNA and at one stage the data appeared to show variations that suggested the dry form might not be helical.
Rosalind was upset that people were claiming it was a helix before her analysis was complete; it was at this stage that she dismissed such premature claims with a joke "funeral" for the dry form being a helix.
Moving to Birkbeck
Rosalind was so unhappy at King's that she negotiated a transfer of her fellowship to Birkbeck, another college in the University of London.
She was also leaving her graduate assistant, Raymond Gosling, at King's. He had helped her take her X-ray photographs and these were remaining at King's: the subject of his thesis.
At the end of January Wilkins showed Watson photo 51 and Watson asked Wilkins for numbers to go with the pattern he had just seen and Wilkins told him what he could.
The numbers Wilkins told Watson gave him (as they had given Rosalind) the length of one turn of the helix (34 Angstroms) which was ten times the spacing between the bases (3.4 Angstroms).
Rosalind, in December 1952, had written a full report on her work, as did all members of the King's Biophysics Unit, to be given to the visiting committee of the Medical Research Council, which paid for the research.
Her data gave full dimensions of the unit cell, its length, width and angles. The MRC report was not expected to be circulated.
In mid February, unbeknown to her, Watson and Crick were shown a copy of the MRC report by their Cavendish colleague, Max Perutz, who was a member of the MRC committee.
It was from the data contained within (including the photograph that Watson had seen earlier) that they were able to add the results of their own investigations and complete the model of the wet form of DNA.
By January she had concluded that wet form was a double helix and by the 24 February 1953 had concluded that both wet and dry form were double helices.
The one missing step was the bases. At this time she believed the A and G bases and the C and T were interchangeable.
This gave her a vision that "an infinite variety of nucleotide sequences would be possible to explain the biological specificity of DNA."
Only months behind?
Both Crick and Watson have since concluded that she was only a matter of months from realising that the bases were paired and not interchangeable and completing the picture.
In my opinion if she had remained at King's there is no doubt that Rosalind would have correctly completed her analysis of the structure in the first half of 1953 without any input from Crick or Watson and that they would not have done so in early 1953 without Rosalind's work.
Rosalind went on to do vital work on viruses, including polio.
She continued doing the research that she loved as long as she could until her cancer was so severe that she could no longer work. She died on 16 April 1958.