Photo 51

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Photo 51, showing X-ray diffraction pattern of DNA

Photo 51 is an X-ray based fiber diffraction image of a paracrystalline gel composed of DNA fiber[1] taken by Raymond Gosling,[2][3] a graduate student working under the supervision of Rosalind Franklin in May 1952 at King's College London, while working in Sir John Randall's group.[4][5][6][7][8] The image was tagged "photo 51" because it was the 51st diffraction photograph that Franklin had taken.[9] It was critical evidence[10] in identifying the structure of DNA.[11]

Use in discovering structure of DNA[edit]

According to Raymond Gosling's later account, although photo 51 was an exceptionally clear diffraction pattern of the "B" form of DNA, Franklin was more interested in solving the diffraction pattern of the "A" form of DNA, so she put Gosling's photo 51 to the side. When it had been decided that Franklin would leave King's College, Gosling showed the photograph to Maurice Wilkins[12][13] (who would become Gosling's advisor after Franklin left).

A few days later, Wilkins showed the photo to James Watson after Gosling had returned to working under Wilkins' supervision. Rosalind Franklin did not know this at the time because she was leaving King's College London. Randall, the head of the group, had asked Gosling to share all his data with Wilkins.[5] Watson recognized the pattern as a helix because his co-worker Francis Crick had previously published a paper of what the diffraction pattern of a helix would be.[12] Watson and Crick used characteristics and features of Photo 51, together with evidence from multiple other sources, to develop the chemical model of the DNA molecule. Their model, along with papers by Wilkins both and colleagues, and by Gosling and Franklin, were first published, together, in 1953, in the same issue of Nature.

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 although there was not yet a rule against posthumous awards,[14] the Nobel Committee generally does not make posthumous nominations.[15] Likewise, Gosling's work was not cited by the prize committee.

The photograph provided key information that was essential for developing a model of DNA.[11][16] The diffraction pattern determined the helical nature of the double helix strands (antiparallel). The outside of the DNA chain has a backbone of alternating deoxyribose and phosphate moieties, and the base pairs, the order of which provides codes for protein building and thereby inheritance, are inside the helix. Watson and Crick's calculations from Gosling and Franklin's photography gave crucial parameters for the size and structure of the helix.[16]

Photo 51 became a crucial data source[17] that led to the development of the DNA model and confirmed the prior postulated double helical structure of DNA, which were presented in the series of three articles in the journal Nature in 1953.

Cartoon explanation of how Photo 51 captured the double helix structure of DNA.

As historians of science have re-examined the period during which this image was obtained, considerable controversy has arisen over both the significance of the contribution of this image to the work of Watson and Crick, as well as the methods by which they obtained the image. Franklin had been hired independently of Maurice Wilkins, who, taking over as Gosling's new supervisor, showed Photo 51 to Watson and Crick without Franklin's knowledge. Whether Franklin would have deduced the structure of DNA on her own, from her own data, had Watson and Crick not obtained Gosling's image, is a hotly debated topic,[11][16][18][19] made more controversial by the negative caricature of Franklin presented in the early chapters of Watson's history of the research on DNA structure, The Double Helix.[16][20][21] Watson admitted his distortion of Franklin in his book, noting in the epilogue: "Since my initial impressions about [Franklin], both scientific and personal (as recorded in the early pages of this book) were often wrong, I want to say something here about her achievements."[22]

Cultural references[edit]

  • A 56-minute documentary, DNA – Secret of Photo 51, was broadcast in 2003 on PBS NOVA.[7] Narrated by Sigourney Weaver, the program features interviews with Wilkins, Gosling, Aaron Klug, Brenda Maddox,[23] including Franklin's friends Vittorio Luzzati, Donald Caspar, Anne Piper, and Sue Richley.[24] The UK version produced by the BBC is titled Rosalind Franklin: DNA's Dark Lady.[25]
  • The first episode of a PBS documentary serial, DNA, which aired on 4 January 2004[26] as "The Secret of Life", centres on and features the contributions of Franklin. Narrated by Jeff Goldblum, it features Watson, Wilkins, Gosling and Peter Pauling (son of Linus Pauling).[27]
  • A play entitled Photograph 51 by Anna Ziegler focuses on the role of X-ray crystallographer Rosalind Franklin in the discovery of the structure of DNA.[28][29] This play won the third STAGE International Script Competition in 2008.[30] In 2015, the play was put on at London West End, with Nicole Kidman playing Franklin.[31]


  1. ^ Franklin, R. E.; Gosling, R. G. (1953-09-10). "The structure of sodium thymonucleate fibres. I. The influence of water content". Acta Crystallographica. 6 (8): 673–677. doi:10.1107/S0365110X53001939.
  2. ^ "Due credit". Nature. 496 (7445): 270. 18 April 2013. doi:10.1038/496270a. PMID 23607133.
  3. ^ Witkowski J (2019). "The forgotten scientists who paved the way to the double helix". Nature. 568 (7752): 308–309. doi:10.1038/d41586-019-01176-9.
  4. ^ Attar, N (2013). "Raymond Gosling: the man who crystallized genes". Genome Biology. 14 (4): 402. doi:10.1186/gb-2013-14-4-402. PMC 3663117. PMID 23651528.
  5. ^ a b Williams, Gareth (2019). Unravelling the Double Helix. New York: Pegasus Books. pp. 264–267. ISBN 978-1-64313-215-0.
  6. ^ "DNA: the King's story". Archived from the original on 2013-02-07. Retrieved 2013-02-15.
  7. ^ a b "Secret of Photo 51. Nova". PBS. Archived from the original on 2017-08-31. Retrieved 2017-09-08.
  8. ^ The gene: a historical perspective. Greenwood Publishing Group. 2007. p. 85. ISBN 9780313334498. PHOTO 51 rosalind franklin.
  9. ^ "PastCast: The other DNA papers". 26 April 2019. Archived from the original on 5 June 2019. Retrieved 4 September 2019.
  10. ^ Krock, Lexi (22 April 2003). "Anatomy of Photo 51". NOVA online. PBS. Archived from the original on 29 July 2010. Retrieved 8 September 2017.
  11. ^ a b c Watson, James D.; Crick, Francis (1953). "A Structure for Deoxyribose Nucleic Acid" (PDF). Nature. 171 (4356): 737–738. Bibcode:1953Natur.171..737W. doi:10.1038/171737a0. PMID 13054692. S2CID 4253007. Archived from the original (PDF) on 2003-04-03.
  12. ^ a b "PastCast: The other DNA papers". 26 April 2019. Archived from the original on 5 June 2019. Retrieved 4 September 2019. Raymond Gosling: 'I took it down the corridor and gave it to him because it had reached the stage now when Rosalind was going to leave, so she suggested that I go down the corridor and give this beautiful structure B pattern, this photo 51, to Maurice. Maurice couldn't believe it when I offered it to him. He couldn't believe that I hadn't stolen it from her desk. He didn't think that she could ever offer him something as interesting as this.'
  13. ^ Tobin, Martin J. (2003-04-15). "April 25, 1953: Three Papers, Three Lessons". American Journal of Respiratory and Critical Care Medicine. 167 (8): 1047–1049. doi:10.1164/rccm.2302011. ISSN 1073-449X. On January 30, 1953, Watson visited King's. Without Franklin's permission, Wilkins showed her data to Watson—in particular, an X-ray crystallograph (of May 1952) that provided unquestionable evidence of the helical structure of DNA.
  14. ^ "Nobel Prize Facts". Official Website of the Nobel Prizes. Archived from the original on 8 July 2017. Retrieved 24 January 2016.
  15. ^ "My aunt, the DNA pioneer". BBC News. 24 April 2003. Archived from the original on 28 August 2007. Retrieved 18 May 2011.
  16. ^ a b c d Maddox, Brenda (2002). Rosalind Franklin: The Dark Lady of DNA. HarperCollins. ISBN 978-0-393-32044-2.
  17. ^ "The instant I saw the picture my mouth fell open and my pulse began to race." James D. Watson (1968), The Double Helix, page 167. New York: Atheneum, Library of Congress card number 68-16217. Page 168 shows the X-shaped pattern of the B-form of DNA which provided details of the helical structure of DNA to both scientists Watson and Crick.
  18. ^ Max Perutz and the Secret of Life. Published in the UK by Chatto & Windus (ISBN 0-7011-7695-4), and in the USA by the Cold Spring Harbor Laboratory Press.
  19. ^ Wilkins; Wilkins, M. (2003). The Third Man of the Double Helix: An Autobiography. Oxford: Oxford University Press.
  20. ^ Watson, James D. (1980) [1968]. The Double Helix: A Personal Account of the Discovery of the Structure of DNA. Atheneum. ISBN 978-0-689-70602-8.
  21. ^ Sayre, Anne (1975). Rosalind Franklin and DNA. New York: W. W. Norton and Company. ISBN 978-0-393-32044-2.
  22. ^ Watson, James D. (1980). Gunther Stent (ed.). The Double Helix: A Personal Account of the Discovery of the Structure of DNA (1980 Norton Critical ed.). W. W. Norton and Company. ISBN 978-0-393-95075-5.
  23. ^ Nathan Southern (2015). "NOVA: DNA – Secret of Photo 51 (2003)". Movies & TV Dept. The New York Times. Archived from the original on 4 February 2015. Retrieved 26 January 2015.
  24. ^ "Secret of Photo 51 Transcript". PBS. Archived from the original on 31 December 2014. Retrieved 26 January 2015.
  25. ^ "Rosalind Franklin: DNA's Dark Lady (2003) (TV)". MoviesPictures.ORG. Archived from the original on 4 February 2015. Retrieved 4 February 2015.
  26. ^ "Season 1, Episode 1 The Secret of Life". TV Guide. Retrieved 26 January 2015.
  27. ^ "Episode 1: The Secret of Life". PBS. Archived from the original on 30 December 2014. Retrieved 26 January 2015.
  28. ^ Kuchment, Anna (January 2011), "For Whom the Nobel Tolls: An evening out with James Watson and colleagues", Scientific American, Nature America, vol. 304, no. 1, p. 27, doi:10.1038/scientificamerican0111-27
  29. ^ Cox, Gordon (April 23, 2015). "Nicole Kidman to Star on West End in 'Photograph 51'". Variety. Archived from the original on 8 September 2015. Retrieved 25 August 2015.
  30. ^ "Ziegler's Photograph 51 Wins STAGE International Script Competition". American Theater Web News. August 5, 2008. Archived from the original on 2015-09-27. Retrieved 25 August 2015.
  31. ^ Porteous, Jacob (24 April 2015). "Nicole Kidman Returns To The West End In Photograph 51". London Theatre Direct. Archived from the original on 16 October 2015. Retrieved 27 October 2015.