Rosalind Franklin

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Rosalind Franklin

Discovery of the DNA Double Helix

Rosalind Franklin
Francis Crick
Rosalind Franklin
James Watson
Maurice Wilkins
Cavendish Laboratory
King's College London
Photo 51

Rosalind Elsie Franklin (25 July 1920 – 16 April 1958) was an English-born physical chemist and crystallographer who made important contributions to the understanding of the fine structures of DNA, viruses, coal and graphite. Franklin is best known for her work on the X-ray Diffraction images of DNA which formed a basis of Watson and Crick's hypothesis of the double helical structure of DNA in their 1953 publication,[1] and when published constituted critical evidence of the hypothesis.[2] In the years following, she led pioneering work on the tobacco mosaic and polio viruses. She died in 1958 of ovarian cancer.

Contents

[edit] Background

Franklin was born in London into an affluent and influential British-Jewish family.[3] Franklin was educated at St Paul's Girls' School[4][5] where she excelled in Latin[6] and sports.[7] Her family were actively involved with a Working Men's College, where Ellis Franklin, her father, taught electricity, magnetism and the history of the Great War in the evenings and later became the vice principal.[8][9] Later they helped settle Jewish refugees from Europe who had escaped the Nazis.[10]

[edit] Education and Career

[edit] University education

In the summer of 1938 Franklin went to Newnham College, Cambridge. She passed her finals in 1941, but was only awarded a decree titular, as women were not entitled to degrees (BA Cantab.) from Cambridge at the time.

[edit] British Coal Utilisation Research Association

She worked for Ronald Norish between 1941 and 1942. Because of her desire to do war work during World War II, she worked at the British Coal Utilisation Research Association in Kingston upon Thames from August 1942, studying the porosity of coal. Her work helped spark the idea of high-strength carbon fibres and was the basis of her doctoral degree-"The physical chemistry of solid organic colloids with special reference to coal and related materials" that she earned in 1945.[11][12]

[edit] Laboratoire central des services chimiques de l'État

After the war ended Franklin accepted an offer to work in Paris with Jacques Mering.[13] She learned x-ray diffraction techniques during her three years at the Laboratoire central des services chimiques de l'État.[14] She seemed to have been very happy there[15] and earned an international reputation based on her published research on the structure of coal.[16] In 1950 she sought work in England[17] and in June 1950 she was appointed to a position at King's College London.[18]

[edit] King's College London

DNA structure
research at
King's College
London
1947-1959
Rosalind Franklin
Raymond Gosling
John Randall
Alec Stokes
Maurice Wilkins
Herbert Wilson
DNA pioneers
William Astbury
Oswald Avery
Erwin Chargaff
Max Delbrück
Jerry Donohue
Raymond Gosling
Phoebus Levene
Linus Pauling
Sir John Randall
Erwin Schrödinger
Alec Stokes
Herbert Wilson

In January 1951, Franklin started working as a research associate at King's College London in the Medical Research Council's (MRC) Biophysics Unit, directed by John Randall.[19] Although originally she was to have worked on x-ray diffraction of proteins in solution, her work was redirected to DNA fibers before she started working at King's.[20][21] Maurice Wilkins and Raymond Gosling had been carrying out x-ray diffraction analysis of DNA in the Unit since 1950.[22]

Franklin, working with her student Raymond Gosling[23] started to apply her expertise in x-ray diffraction techniques to the structure of DNA. They discovered that there were two forms of DNA: at high humidity (when wet) the DNA fiber became long and thin, when it was dried it became short and fat.[24][25] These were termed DNA 'B' and 'A' respectively. The work on DNA was subsequently divided, Franklin taking the A form to study and Wilkins the 'B' form.[26][27] The x-ray diffraction pictures taken by Franklin at this time have been called, by J. D. Bernal, "amongst the most beautiful x-ray photographs of any substance ever taken".[28]

By the end of 1951 it was generally accepted in King's that the B form of DNA was a helix, but Franklin in particular was unconvinced that the A form of DNA was helical in structure.[29] As a practical joke Franklin and Gosling produced a death notice regretting the loss of helical crystalline DNA (A-DNA).[30] During 1952 Rosalind Franklin and Raymond Gosling worked at applying the Patterson function to the x-ray pictures of DNA they had produced,[31] this was a long and labour-intensive approach but would give an insight into the structure of the molecule.[32][33]

Franklin and Gosling death notice for a helical structure for crystalline DNA (or A-DNA)
Franklin and Gosling death notice for a helical structure for crystalline DNA (or A-DNA)

In February 1953 Francis Crick and James D. Watson of the Cavendish Laboratory in Cambridge University had started to build a model of the B form of DNA using similar data to that available to the team at King's. Model building had been applied successfully in the elucidation of the structure of the alpha helix by Linus Pauling in 1951,[34][35] but Rosalind Franklin was opposed to building theoretical models, taking the view that building a model was only to be undertaken after the structure was known.[36][37] Watson and Crick then indirectly obtained a prepublication version of Franklin's DNA X-ray diffraction data possibly without her knowledge, and a prepublication manuscript by Pauling and Corey, giving them critical insights into the DNA structure.[38]

Francis Crick and James Watson then published their model in Nature on 25 April 1953 in an article describing the double-helical structure of DNA with a small footnote to Franklin's data.[39] Articles by Wilkins and Franklin illuminating their x-ray diffraction data published in the same issue of Nature supported the Crick and Watson model for the B form of DNA.[40][41] Franklin eventually left King's College London in March 1953 to move to Birkbeck College in a move that had been planned for some time.[42]

[edit] Birkbeck College, London

Electronmicrograph of Tobacco Mosaic Virus
Electronmicrograph of Tobacco Mosaic Virus

Franklin's work in Birkbeck involved the use of x-ray crystallography to study the structure of the tobacco mosaic virus (TMV) under J. D. Bernal[43] and was funded by the Agricultural Research Council(ARC).[44] In 1954 Franklin began a longstanding and successful collaboration with Aaron Klug.[45] In 1955 Franklin had a paper published in the journal Nature, indicating that TMV virus particles were all of the same length,[46] this was in direct contradiction to the ideas of the eminent virologist Norman Pirie, though her observation ultimately proved correct.[47]

Franklin worked on rod like viruses such as TMV with her Ph.D. student Kenneth Holmes, while Aaron Klug worked on spherical viruses with his student John Finch, Franklin coordinated the work and was in charge.[48] Franklin also had a research assistant, James Watt, subsidised by the National Coal Board and was now the Leader of the "ARC Group" at Birkbeck.[49] By the end of 1955 her team had completed a model of the TMV and were working on viruses affecting several plants, including potato, turnip, tomato and pea.[50] Franklin and Don Casper produced a paper each in Nature that taken together demonstrated that the RNA in TMV is wound along the inner surface of the hollow virus.[51][52]

[edit] Illness and death

In the summer of 1956, while on a work related trip to the United States of America (USA) Franklin first began to suspect a health problem.[53] An operation in September of the same year revealed two tumors in her abdomen.[54] After this period of illness Franklin spent some time convalescing at the home of Crick and his wife Odile.[55] She continued to work and her group continued to produce results, seven papers in 1956 and a further six in 1957.[56] In 1957 the group was also working on the polio virus and had obtained funding from the Public Health Service of the National Institutes of Health in the USA.[57] At the end of 1957 Franklin again fell ill and was admitted to the Royal Marsden Hospital. She returned to work in January 1958 and was given a promotion to Research Associate in Biophysics.[58] She fell ill again on the 30th of March and died on the 16th of April of ovarian cancer.[59] Exposure to X-ray radiation is sometimes considered a possible factor in her illness, though she was no more reckless than other laboratory staff of the time. Other members of her family have died of cancer, and the incidence of cancer is known to be disproportionately high amongst Ashkenazi Jews.[60]

[edit] Controversies after death

Various controversies have surrounded Rosalind Franklin; these have all come to light after her death.

[edit] Allegations of sexism at King's College

There have been allegations that Rosalind Franklin was discriminated against because of her gender:

One of the allegations is that King's, as an institution, was sexist. The allegation held that women were excluded from the staff dining room, and had to eat their meals in the student hall or away from the University.[61][62] Whereas it is true that there was a dining room for the exclusive use of men (as was the case at other University of London colleges at the time), there was also a mixed gender dining room that overlooked the river Thames, and many male scientists refused to use the male only dining room owing to the preponderance of theologians.[63]

The other accusation regarding gender is that women were under-represented in John Randall's group; there was only one other woman in the group and that women were unfairly excluded.[64] In contrast, defenders of the college argue that women were (by the standards of the time) well-represented in the group, representing eight out of thirty-one members of staff (approximately one in four).[65]

[edit] Contribution to the model of DNA

Rosalind Franklin's contributions to the Crick and Watson model include an X-ray photograph of B-DNA (called photograph 51),[66] that was briefly shown to James Watson by Maurice Wilkins in January 1953,[67][68] and a report written for an MRC biophysics committee visit to King's in December 1952. The report contained data from the King's group, including some of Rosalind Franklin's work, and was given to Francis Crick by his thesis supervisor Max Perutz, a member of the visiting committee.[69][70] Maurice Wilkins had been given photograph 51 by Rosalind Franklin's PhD student Raymond Gosling, because she was leaving King's to work at Birkbeck, there was nothing untoward in this,[71][72] though it has been implied, incorrectly, that Maurice Wilkins had taken the photograph out of Rosalind Franklin's drawer.[73] Likewise Max Perutz saw no harm in showing the MRC report to Crick as it had not been marked as confidential. Much of the important material contained in the report had been presented by Franklin in a talk she had given in November 1951, which Watson had attended.[74][75] The upshot of all this was that when Crick and Watson started to build their model in February 1953 they were working with very similar data to those available at King's. Rosalind Franklin was probably never aware that her work had been used during construction of the model.[76]

[edit] Recognition of her contribution to the model of DNA

On the completion of their model, Francis Crick and James Watson had invited Maurice Wilkins to be a co-author of their paper describing the structure.[77][78] Wilkins turned down this offer, as he had taken no part in building the model.[79] Maurice Wilkins later expressed regret that greater discussion of co-authorship had not taken place as this may have helped to clarify the contribution the work at King's had made to the discovery.[80] There is no doubt that Franklin's experimental data were used by Crick and Watson to build their model of DNA in 1953 (see above). That she is not cited in their original paper outlining their model may be a question of circumstance, it would have been very difficult to cite the unpublished work from the MRC report they had seen.[81] It should be noted that the x-ray diffraction work of both Wilkins and William Astbury are cited in the paper, and that the unpublished work of both Franklin and Wilkins are acknowledged in the paper.[1]Franklin and Raymond Gosling's own publication in the same issue of Nature was the first publications of this more clarified X-ray image of DNA.[82]

[edit] Nobel Prize

The rules of the Nobel Prize forbid posthumous nominations.[83] Because Rosalind Franklin had died in 1958 she was not eligible for the Nobel Prize subsequently awarded to Crick, Watson, and Wilkins in 1962.[84] The award was for their body of work on nucleic acids and not exclusively for the discovery of the structure of DNA.[85] By the time of the award Wilkins had been working on the structure of DNA for over ten years, and had done much to confirm the Crick-Watson model.[86] Crick had been working on the genetic code at Cambridge and Watson had worked on RNA for some years. [87]

[edit] Posthumous recognition

a) on the base:

i) "These strands unravel during cell reproduction. Genes are encoded in the sequence of bases."

ii) "The double helix model was supported by the work of Rosalind Franklin and Maurice Wilkins."

b) on the helices:

i) "The structure of DNA was discovered in 1953 by Francis Crick and James Watson while Watson lived here at Clare."

ii) "The molecule of DNA has two helical strands that are linked by base pairs Adenine - Thymine or Guanine - Cytosine."

[edit] Footnotes

  1. ^ a b A Structure for Deoxyribose Nucleic Acid. Watson J.D. and Crick F.H.C. Nature 171, 737-738 (1953)
  2. ^ Double Helix: 50 Years of DNA. Nature archives. Nature Publishing Group
  3. ^ Maddox p. 3
  4. ^ Maddox p. 25
  5. ^ Sayre p. 41
  6. ^ Maddox p. 30
  7. ^ Maddox, p. 26
  8. ^ Maddox, p. 20
  9. ^ Sayre, p. 35
  10. ^
  11. ^ Maddox, pp.40-82
  12. ^ Sayre pp. 47-57
  13. ^ Maddox, page 87
  14. ^ Maddox, p. 88
  15. ^ Maddox, p. 92
  16. ^ Franklin (1950)
  17. ^ Maddox, p. 108
  18. ^ Maddox, p. 111
  19. ^ Maddox, p. 124
  20. ^ Maddox, p. 114
  21. ^ Wilkins, pp. 143-144
  22. ^ Wilkins, p. 121
  23. ^ Maddox, p. 129
  24. ^ Maddox, p. 153
  25. ^ Wilkins, p. 154
  26. ^ Wilkins, p. 158
  27. ^ Maddox, p. 155
  28. ^ Maddox, p. 153
  29. ^ Wilkins, p. 176
  30. ^ Wilkins, p. 182
  31. ^ Maddox, p. 168
  32. ^ Maddox, p. 169
  33. ^ Wilkins, pp. 232-233
  34. ^ Maddox, p. 147
  35. ^ Wilkins, p. 158
  36. ^ Maddox, p. 161
  37. ^ Wilkins, p. 176
  38. ^ Yockey, pp. 9-10.
  39. ^ Maddox, p. 212
  40. ^ Franklin and Gosling (1953)
  41. ^ Maddox, p. 210
  42. ^ Maddox, p. 168
  43. ^ Maddox, p. 229
  44. ^ Maddox, p. 235
  45. ^ Maddox, p. 249
  46. ^ Franklin (1955)
  47. ^ Maddox, p. 252
  48. ^ Maddox, p. 254
  49. ^ Maddox, p. 256
  50. ^ Maddox, p. 262
  51. ^ Maddox, p. 269
  52. ^ Franklin (1956)
  53. ^ Maddox, p. 284
  54. ^ Maddox, p. 285
  55. ^ Maddox, p. 288
  56. ^ Maddox, p. 292
  57. ^ Maddox, p. 296
  58. ^ Maddox, p. 302
  59. ^ Maddox, pp. 305-307
  60. ^ Maddox, p.320
  61. ^ Sayre, p.97
  62. ^ Bryson, B. (2004) p. 490
  63. ^ Maddox, p. 128
  64. ^ Sayre, p.99
  65. ^ Maddox, p. 133
  66. ^ Maddox, pp. 177-178
  67. ^ Maddox, p. 196
  68. ^ Crick, (1988) p. 67.
  69. ^ Elkin, L.O. (2003)
  70. ^ Maddox, pp. 198-199
  71. ^ Maddox, pp. 196
  72. ^ Wilkins, p. 198
  73. ^ Wilkins, p. 257
  74. ^ Maddox, p. 199
  75. ^ Watson (1969).
  76. ^ Maddox, p. 316
  77. ^ Wilkins, p. 213
  78. ^ Maddox, p. 205
  79. ^ Wilkins, p. 214
  80. ^ Wilkins, p. 226
  81. ^ Maddox, p. 207
  82. ^ Franklin R, Gosling RG (1953) "Molecular Configuration in Sodium Thymonucleate". Nature 171: 740–741. Full text PDF
  83. ^ Maddox, p. 205
  84. ^ Nobel Prize (1962)
  85. ^ Wilkins, p. 242
  86. ^ Wilkins, p. 240
  87. ^ Wilkins, p. 243
  88. ^ a b c Maddox, p. 322
  89. ^ Sir Aaron Klug opens new Laboratory
  90. ^ NPG pictures
  91. ^ Maddox, p. 323
  92. ^ The Royal Society Rosalind Franklin Award (2003): The Royal Society web page. Retrieved 21 July 2006.
  93. ^ Dedication of Rosalind Franklin University

[edit] References

[edit] Further reading

  • Brown, Andrew, J. D. Bernal: The Sage of Science (Oxford University Press 2005).
  • Chomet, S. (Ed.), D.N.A. Genesis of a Discovery. Newman-Hemisphere Press (1994): NB a few copies are available from Newman-Hemisphere at 101 Swan Court, London SW3 5RY (phone/fax: 07092 060530).
  • Freeland Judson, Horace [1977] (1996). The Eighth Day of Creation: Makers of the Revolution in Biology, Expanded edition, Plainview, N.Y: CSHL Press. ISBN 0-87969-478-5. 
  • Glynn, Jennifer Franklin. "Rosalind Franklin, 1920 - 1958" in "Cambridge Women: Twelve Portraits" (CUP 1996) pp 267 - 282 eds. Edward Shils and Carmen Blacker, ISBN 0521482879
  • Klug, A. A lecture about Rosalind Franklin's contribution to the elucidation of the structure of DNA. in DNA Changing Science and Society: The Darwin Lectures for 2003 Krude, Torsten (Ed.) CUP (2003)
  • Olby, Robert, The Path to The Double Helix: Discovery of DNA, (1974). MacMillan ISBN 0-486-68117-3
  • "Quiet debut for the double helix" by Professor Robert Olby, Nature 421 (January 23, 2003): 402-405.
  • Tait, Sylvia & James "A Quartet of Unlikely Discoveries" (Athena Press 2004) ISBN 184401343X
  • Watson, James D. (1980). The double helix: A personal account of the discovery of the structure of DNA. Norton. ISBN 0-393-01245-X. 

[edit] See also

[edit] External links

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