Background

Rosalind Elsie Franklin was born on July 25, 1920, in London, England. She was the second child and first daughter of Ellis and Muriel (Waley) Franklin. Her family's background was in banking and the arts. Yet, by the age of 15, she had chosen science as her vocation. Years later she still debated this decision with her father, who eventually accepted it even though it meant, at that time, a choice of career over marriage and family life.

Education

Following St. Paul's Girls' School in London, Franklin went to Cambridge University in 1938 as a chemistry student at Newnham College. In 1945 she received her Ph.D. for a thesis on "The Physical Chemistry of Solid Organic Colloids with Special Relation to Coal and Related Materials."

Career

After graduating in 1941 Rosalind stayed in Cambridge to investigate gas-phase chromatography under Ronald Norrish. In 1942 she joined the British Coal Utilisation Research Association where, under D. H. Bangham, she applied her expertise in physical chemistry to the problem of the physical structure of coals and carbonized coals. From 1947 to 1950 Franklin worked under Jacques Méring at the Laboratoire Central des Services Chimiques de l’État, Paris, where she developed her skill in X-ray diffraction techniques and applied them to a detailed and illuminating study of carbons and of the structural changes accompanying graphitization. In 1951 she joined Sir John Randall’s Medical Research Council unit at King’s College, London, to apply these techniques to the problems of the structure of DNA, and in 1953 she moved to Birkbeck College, London, to work similarly on the even more exacting problems of virus structure.

At the British Coal Utilisation Research Association, Franklin developed, with Bangham and other workers, a hypothesis of the micellar organization of coals which provided a satisfactory explanation of their absorptive behavior toward liquids and gases and their thermal expansion. From her study of the fine porosity of a range of coals, by measurements of true and apparent densities, Franklin concluded that their structure was best represented by a model with pore constrictions which gave coals the properties of molecular sieves. In Paris she turned her attention to the application of X-ray diffraction methods to the problems of carbon structure and developed a procedure for the detailed interpretation of the diffuse X-ray diagram of carbons. This allowed her to describe the structure in more precise quantitative terms than had been possible, and she made use of it to study in detail the structural changes that accompanied the formation of graphite when these carbons were heated to high temperatures.

In the course of this work, Franklin developed a relation between the apparent interlayer spacing of the partially graphitized carbons and the proportion of disoriented layers, which has proved of considerable value in the industrial study of carbons. In addition, by studying the changes in structure that chars of different origin underwent on heating, she established that there are two distinct classes of carbons - those which form graphite on heating to high temperatures (the graphitizing carbons) and those which do not (the nongraphitizing carbons) - and related these differences in behavior to structural differences in the parent chars. She showed, in particular, that the graphilizability increases with the fine structure porosity and this, in turn, she believed to be related to the cross-linking between the crystallites.

Franklin’s work on coals brought her into contact with Charles Coulson, through whom she was introduced to Randall, and with the award of a Turner Newall Fellowship, she went to work in the King’s College Medical Research Council Biophysics Unit. At that time Raymond Gosling, under M. H. F. Wilkins’ direction, had obtained diffraction pictures of DNA showing a high degree of crystallinity.

Franklin and Gosling conducted a systematic study of the effect of humidity on the X-ray pattern produced. Using salt solutions to control humidity, they showed that there are two distinct intramolecular patterns, which they found to be producible from the same specimen: the crystalline “A” pattern at 75 percent relative humidity and a new “wet” paracrystalline pattern at 95 percent relative humidity. In a report which Franklin gave on this work in November 1951, she described this discovery and went on to show, as Wilkins had a year before in Cambridge, that the patterns were consistent with a helical conformation. She said little about the forces operating inside the helices but mentioned hydrogen bonding between keto and amino groups of the bases.

Despite this promising beginning, Franklin was too professional a crystallographer to proceed further in this way. Instead, she thought to solve the structure of DNA by using Patterson functions and superposition. While publicly she heaped scorn on those who were convinced that DNA is helical, in her unpublished reports she stated that such a conformation is probable for the B form and not inconsistent with the A form. A spurious case of double orientation encountered in April 1952, which when indexed showed marked radial asymmetry, led her to seek nonhelical structures for the A form. Earlier ambiguities in the indexing of the A diagram had led Franklin to embark on a Patterson analysis. This helped her to obtain accurate parameters for the unit cell. Yet the cylindrical Patterson function obtained by Gosling in July 1952 strengthened her antihelical views, although the arrangement of peaks was consistent with a helix. She was misled, by what appeared to be clear evidence of a structural repeat at half the height of the unit cell, into ruling out helices for the A form, since no DNA chain could possibly be folded into a helix with a pitch equal to half the height of the unit cell.

At this time Franklin was thinking in terms of antiparallel rods in pairs back-to-back, forming a double sheet structure. Then she investigated diagonal rod structures such as would simulate the diffraction pattern of a helix, but by January 1953, when she started model building, she found such structures impossible to build. Still rejecting single- or multistrand helices, she investigated a figure-eight structure in which a single chain formed a long column of repeating eights. This, she believed, would account for the halving of the unit cell in the cylindrical Patterson function and clearly provided a form of tight packing which could be unfolded to give the dramatic increase in length (30 percent) when structure A changes to structure B. She knew that the helix in the extended B form is close-packed and was doubtful that the same type of structure could pack down even more densely.

At the end of February 1953, Franklin turned to the B pattern, and for two weeks she weighed the merits of single and multiple helices. In a paper dated 17 March which she wrote with Gosling, she ruled out triple-strand and equally spaced double-strand helices. This is the conformation of the sugar-phosphate backbones as found in the Watson-Crick model. On the following day, Franklin returned to the Patterson function of the A form, only to learn that Watson and Crick had solved the structure of the B form. She and Gosling quickly expanded and rearranged their draft paper of 17 March in the light of the Cambridge discovery so that it could appear in the 25 April issue of Nature, which contains Watson and Crick’s paper on their model.

Franklin deserves credit for having discovered the A B transformation and characterized the diffraction patterns of these forms of DNA; for providing Watson and Crick with vital data, in particular the parameters of the unit cell; for exposing the errors in their first unpublished model; and for marshaling the evidence in favor of the phosphates being on the outside of the helix. It was also she who, with the aid of the special tilting camera built by Gosling, discovered the meridional reflection on the eleventh layer line in the A pattern and was the first to show how the B form can pack down more tightly to give the A form with eleven residues in one turn of the helix. Although she had been misled by the cylindrical Patterson function, this did provide the most refined evidence in favor of the Watson-Crick model at the time of its discovery in 1953. Franklin and Gosling’s rarely cited paper on this subject appeared in Nature on 25 July 1953.

For the last five years of her life, Franklin worked in the Crystallography Laboratory of Birkbeck College, London, supported first by the Agricultural Research Council and later by the United States Department of Health. There she continued to publish on her earlier work on coals, completed the writing up of her DNA work, and took up the structure of tobacco mosaic virus. By 1956 she had greatly improved on J.D. Watson’s X-ray pictures of 1954. From a study of the X-ray diagram of TMV, Franklin and Klug resolved the discrepancy between estimates of the maximum radius and the packing radius by postulating the morphology of the protein as “a helical array of knobs, one knob for each sub-unit.” Shortly before her death from cancer, Franklin instituted work which was later to justify her conclusion that the RNA in TMV is present in the form of a single-strand helix.

Achievements

• Rosalind Franklin was an outstanding scientist best known for her contributions to the discovery of the molecular structure of deoxyribonucleic acid (DNA), a constituent of chromosomes that serves to encode genetic information. She also contributed new insight on the structure of viruses, helping to lay the foundation for the field of structural virology. In 2003, the Royal Society established the Rosalind Franklin Award for an outstanding contribution to any area of natural science, engineering or technology.
  
  

Personality

Franklin proved to be a gifted scientist and a determined personality. Once, she knelt accidentally on a sewing needle and walked to a hospital to have it removed; the astonished doctor was amazed that she could have walked with a needle angled across her knee joint. She applied the same resolve to her studies. During her college years, World War II often disrupted classes and students were forced to work independently much of the time. Franklin throve in this atmosphere, working long hours in the laboratory and developing work habits that would serve her well in the future.

Quotes from others about the person

• "As a scientist Miss Franklin was distinguished by extreme clarity and perfection in everything she undertook. Her photographs are among the most beautiful X-ray photographs of any substance ever taken. She was an admirable director of a research team and inspired those who worked with her to reach the same high standards." - head of the laboratory at Birkbeck

Connections

Father:

Ellis Franklin

Mother:

Muriel Waley Franklin

Friend:

Anne Sayre

Friend:

Francis Crick

References

• My Sister Rosalind Franklin: A Family Memoir
• Rosalind Franklin: The Dark Lady of DNA
• Dictionary of Scientific Biography