Maurice Wilkins, who had worked on the atom bomb project during the Second World War, was another scientist who chose to change his focus from death to life. He moved to a unit that used experimental physical techniques to study life at King’s College, London. From the USA he brought an interest in the challenge of the genetic code: Could DNA be seen as information encoded in a fibrous structure? Could it be revealed by X-ray crystallography? DNA is difficult to work with, but Wilkins managed to draw out fibres that could be X-rayed.
Rosalind Franklin, an expert on X-ray crystallography, joined Wilkins at King's. She also started work on DNA, obtaining excellent images. Her working relationship with Wilkins, however, was never made clear. While she thought DNA was her personal project, Wilkins thought they were collaborating. Although Wilkins was convinced that the images of DNA indicated a helical structure, Franklin was more cautious. Nonetheless, in 1952 Rosalind Franklin made the X-ray crystallography image that would be used to support the proposition that DNA had a helical structure.
At the same time as Rosalind Franklin and Maurice Wilkins were conducting their research in London, in Cambridge a young American visitor and a slightly older British veteran of wartime radar development were also studying the structure of DNA. Crick and Watson made use of Rosalind Franklin’s data. They combined chemical evidence from the USA about the pairing of chemical groups called bases with the X-ray evidence, and proposed a structure of two matching helices like a twisted ladder. They showed that each helix determined its mate and that, by separating them, each helix created the template for new identical DNA molecules.
Later, in his book The Double Helix, Watson wrote about how excited the two men were by this realisation. He describes how Crick ran into the Eagle pub in Cambridge shouting that he had found the ‘secret of life’.
In 1958 Rosalind Franklin died of cancer. In 1963 Crick, Watson and Wilkins were awarded the Nobel Prize. Controversy has continued as to whether Franklin’s role in understanding the structure of DNA has been properly acknowledged.