<P> In 1937, William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure . </P> <P> In 1943, Oswald Avery, along with coworkers Colin MacLeod and Maclyn McCarty, identified DNA as the transforming principle, supporting Griffith's suggestion (Avery--MacLeod--McCarty experiment). DNA's role in heredity was confirmed in 1952 when Alfred Hershey and Martha Chase in the Hershey--Chase experiment showed that DNA is the genetic material of the T2 phage . </P> <P> Late in 1951, Francis Crick started working with James Watson at the Cavendish Laboratory within the University of Cambridge . In 1953, Watson and Crick suggested what is now accepted as the first correct double - helix model of DNA structure in the journal Nature . Their double - helix, molecular model of DNA was then based on one X-ray diffraction image (labeled as "Photo 51") taken by Rosalind Franklin and Raymond Gosling in May 1952, and the information that the DNA bases are paired . On 28 February 1953 Crick interrupted patrons' lunchtime at The Eagle pub in Cambridge to announce that he and Watson had "discovered the secret of life". </P> <P> Months earlier, in February 1953, Linus Pauling and Robert Corey proposed a model for nucleic acids containing three intertwined chains, with the phosphates near the axis, and the bases on the outside . Experimental evidence supporting the Watson and Crick model was published in a series of five articles in the same issue of Nature . Of these, Franklin and Gosling's paper was the first publication of their own X-ray diffraction data and original analysis method that partly supported the Watson and Crick model; this issue also contained an article on DNA structure by Maurice Wilkins and two of his colleagues, whose analysis and in vivo B - DNA X-ray patterns also supported the presence in vivo of the double - helical DNA configurations as proposed by Crick and Watson for their double - helix molecular model of DNA in the prior two pages of Nature . In 1962, after Franklin's death, Watson, Crick, and Wilkins jointly received the Nobel Prize in Physiology or Medicine . Nobel Prizes are awarded only to living recipients . A debate continues about who should receive credit for the discovery . </P>

Who proposed the double helical model of dna