The discovery that DNA is a double helix and that this structure comprises the hereditary material of living cellular organisms is perhaps the most momentous of our era. The discovery paved the way for new research in areas such as gene therapy for inherited diseases, the sequencing of the human genome, and biotechnology.
The prime movers in obtaining the data that underpinned Watson and Crick’s model were Maurice Wilkins, who had commenced pilot studies on the use of X-rays to analyse DNA structure, and Rosalind Franklin, who advanced the X-ray resolution of DNA structure to a new level of clarity and sophistication.
Maurice Wilkins (1916 -2004) studied physics at Cambridge then in John Randall’s (1905-1984) department at the University of Birmingham. His early work, during the Second World War, contributed to the Manhattan project. Partly in reaction to the use of the atomic bomb in Japan and the continuing threat to human life, Wilkins was attracted to the possibility of applying his knowledge to a more useful and intellectually attractive field through biophysics. He teamed up with Randall again, first at St Andrew’s and then at King’s, where Randall was invited to head the new MRC Biophysics Unit in 1946. This unit was the first to bring biologists, physicists and chemists together to study biological problems. At that time it was not generally accepted that DNA was the cell’s genetic material, but Randall and Wilkins, persuaded that it was, pressed ahead to examine its structure by X-ray diffraction. Wilkins, working with a PhD student Raymond Gosling (b 1926), later Professor of Physics in Medicine at Guy’s, obtained in 1950 the first clear X-ray diffraction pattern of DNA. Their colleague Alec Stokes (1919-2003), a physicist and mathematician, deduced that this pattern was due to a helical structure.
Randall also invited Rosalind Franklin (1920 -1958) to join the unit and study the structure of DNA. Aged 30, Franklin already had a reputation as an excellent scientist; she had graduated from Cambridge in chemistry, then pursued significant work on the microstructure of graphite and coal before spending three years in Paris gaining extensive experience in X-ray diffraction. Franklin strengthened the DNA project, but although she and Wilkins discussed their results, they regarded themselves as working on separate programmes. Franklin took over the supervision of Gosling’s PhD thesis and they found DNA to have two forms – ‘A’ and ‘B’ – depending on water content, and with different diffraction patterns, ‘A’ being the form already characterized by Wilkins and Gosling.
Meanwhile Crick and Watson were building models of DNA structure at Cambridge. There was a continual exchange of information between the two institutions. No model had yet satisfied the complex and expanding information on DNA’s 3D structure and its chemical composition. In early 1953 Wilkins showed Watson a picture of ‘B’ DNA from Franklin’s work, seemingly without her knowledge, believing that the information was communal. Shortly afterwards the Cambridge group received the MRC’s report on its site visit (December 1952) to Randall’s department. The new information led Crick and Watson to a further model which was viewed by Wilkins in March 1953 and recognized by him to accord with his and Franklin’s work, yet giving him new insight to DNA’s structure too.
The latest Cambridge model was the basis of the famous publication by Watson and Crick in Nature, April 1953, proposing the structure of DNA, which appeared as a sequence of three papers on DNA (the other two being by Wilkins, Stokes and Wilson, and Franklin and Gosling, on the X-ray diffraction data and structural conclusions of DNA preparations). Other proposals for the structure of DNA were being made, and over the next seven years Wilkins and his colleague, Herbert Wilson (b 1929), a physicist specialising in X-ray diffraction, undertook further structural studies to confirm Watson and Crick’s proposed structure of the double helix. For this work and his earlier studies on DNA, Wilkins shared with Crick and Watson the Nobel Prize for Medicine or Physiology in 1962. Franklin had died from cancer in 1957; the Nobel Prize is not awarded posthumously and is not shared between more than three laureates.
The combination of work eventually resulting in the discovery of DNA’s structure and function was recognized at the time by Nature in publishing the three seminal papers back to back; the award of the Nobel Prize, which by its constitution can recognize groups as much as individuals, to the three laureates; and above all to acknowledge the benefits already achieved and yet to come from the leap in understanding of heredity.
The pioneering researchers are commemorated in the name of the Franklin-Wilkins Building at Waterloo, where members of the School of Biomedical Sciences are now based