Sometime in May 1952 Raymond Gosling, a doctoral candidate under Rosalind Franklin at the Wheatstone Physics Laboratory, King’s College, took some 35 strands of sodium thymonucleate obtained from a calf thymus, stretched them taut across a paperclip mounted to a cork with rubber cement and sealed the makeshift assembly in a camera fitted to an X-ray tube. Gosling then bubbled water and hydrogen through the camera and exposed the film for nearly 90 hours. Later he recalled “looking at the developer, and up through the tank swam this beautiful spotted photograph.” The “spotted photograph”, now known simply as Photo 51, was to anyone who could interpret it the first clear evidence of the structure of DNA. It would become the most iconic photograph in the history of biology.
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