Rosalind Franklin

Rosalind Franklin was an English chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA, of RNA, and of viruses. Her X-ray diffraction images provided crucial evidence for the double helix model of DNA.

Early Life and Education

Franklin was born in 1920 in London to a family of prosperous bankers. She was educated at St Paul's Girls' School and at Newnham College, Cambridge, where she read chemistry.

She worked during the Second World War on the physical chemistry of coal and on the structure of carbon. The work earned her a doctorate from Cambridge in 1945.

She then spent three years in Paris, where she learned the techniques of X-ray diffraction crystallography at the Laboratoire Central des Services Chimiques de l'État.

The DNA Research

Franklin joined King's College London in 1951 and was assigned to work on the structure of DNA. She used X-ray diffraction to produce images of exceptional quality.

Her photograph 51, taken in 1952, showed the helical structure of the molecule with great clarity. She also established the density and the water content of the fibre.

Her data were shown to James Watson without her knowledge or consent by Maurice Wilkins, her colleague at King's College. The information contributed to the model published by Watson and Crick in 1953.

The Double Helix

The model proposed by Watson and Crick was published in Nature in April 1953, alongside papers by Wilkins and by Franklin. The structure explained how genetic information could be stored and copied.

Franklin's contribution was not fully acknowledged at the time. Her photograph and her measurements were essential to the solution of the structure.

The publication of Watson's book The Double Helix in 1968 provoked controversy over the treatment of Franklin and over the ethics of the research.

Later Work and Death

Franklin left King's College in 1953 and moved to Birkbeck College, where she worked on the structure of viruses. She made important contributions to the understanding of tobacco mosaic virus and of polio virus.

She died of ovarian cancer in 1958 at the age of thirty-seven. The cause may have been related to her exposure to X-rays.

The Nobel Prize for the discovery of the structure of DNA was awarded in 1962 to Watson, Crick, and Wilkins. Franklin was not eligible because the prize is not awarded posthumously.

Legacy

Franklin's contribution to the discovery of the structure of DNA is now widely recognised. She is regarded as one of the most important scientists of the twentieth century.

Her work on viruses laid the foundations for later research in structural biology. She is also remembered as a pioneer for women in science.

Her photograph 51 has become an icon of scientific discovery. Her life and her treatment by her contemporaries continue to be discussed.

The Structure of DNA

Franklin produced X-ray diffraction photographs of DNA that revealed its helical structure. The images were of exceptional quality and required great technical skill.

She established that the molecule has two forms, the dry A form and the wet B form, and she measured the dimensions of the helix. She also determined that the phosphate groups are on the outside of the molecule.

Her evidence was essential to the model proposed by Watson and Crick, who built their model after seeing her data. The double helix explained the mechanism of heredity.

The Controversy

The publication of Watson's book The Double Helix in 1968 brought the events to public attention. Watson's account was criticised for its treatment of Franklin and for its inaccuracies.

The question of whether Franklin's data were used without her consent has been debated. Wilkins showed her photograph to Watson, and the information was used in the model.

Franklin was not informed of the use of her data, and she died before the Nobel Prize was awarded. The episode has become a case study in the ethics of scientific collaboration.

The Virus Research

Franklin turned to the study of viruses after leaving King's College. She worked on the tobacco mosaic virus and determined the arrangement of its protein subunits.

She also worked on the polio virus and on other plant and animal viruses. Her work contributed to the understanding of viral structure and of infection.

She built a research group at Birkbeck College and supervised students. Her work was supported by the Agricultural Research Council and by the National Foundation for Infantile Paralysis.

Recognition

Franklin's contribution to the discovery of the structure of DNA is now widely recognised. Her photograph 51 is one of the most famous images in science.

The Rosalind Franklin University of Medicine and Science and several other institutions are named in her honour. The Royal Society has established a medal in her name.

Her life has been the subject of biographies, plays, and films. She is remembered as a scientist of great ability and as a pioneer for women in science.

Assessment

Historians of science differ on the assessment of her role. Some emphasise the centrality of her data, while others note that the model required insight and interpretation.

Her scientific achievements in their own right, particularly in the study of viruses, are substantial. She was a meticulous experimentalist and a rigorous thinker.

She is remembered as a victim of the conventions of her time, but also as a scientist who made a decisive contribution to one of the great discoveries of the century.

See also

• DNA structure
• X-ray crystallography