<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Photograph 51 is the nickname given to an X-ray diffraction image of crystallized DNA taken by Raymond Gosling in May 1952, working as a PhD student under the supervision of Rosalind Franklin, at King's College London in Sir John Randall's group . It was critical evidence in identifying the structure of DNA . </P> <P> James Watson was shown the photo by Maurice Wilkins without Rosalind Franklin's approval or knowledge (although by this time Gosling had returned to the supervision of Wilkins). Along with Francis Crick, Watson used characteristics and features of Photo 51 to develop the chemical model of the DNA molecule . In 1962, the Nobel Prize in Physiology or Medicine was awarded to Watson, Crick and Wilkins . The prize was not awarded to Franklin; she had died four years earlier, and the Nobel Prize's rules require that it be awarded only to living persons . </P>

How many strands of dna is shown in photograph 51