Sunday, July 25, 2010
Rosalind Elsie Franklin
Rosalind Elsie Franklin was born in London, England on July 25, 1920, the second of five children of a prominent Anglo-Jewish family. Her father Ellis Franklin was a partner at Keyser's Bank and her mother Muriel (Waley) Franklin was active in charity work. Growing up with brothers, both older and younger, Franklin became more interested in sports and competitions than girlish things. In 1932, at age eleven, Franklin entered St. Paul's School for Girls and at the competitive school she showed an aptitude for math and science in addition to a facility for languages.
Franklin left St. Paul's in 1936, entering Newnham College at Cambridge (one of the two women's colleges at Cambridge) to major in physical chemistry. She was awarded her B.A. in 1941 and received a scholarship and a grant to do research for a year under R.G.W. Norrish's supervision. Afterwards, with the war on, Franklin was able to find a position doing research for the newly formed British Coal Utilization Research Association. Her research involved studying the microstructure of coal. Measuring the density with different liquids and helium gas she was able to determine the amount of small pores in a sample of coal. When the coal was heated to carbonizing temperatures the amount of pores increased. Her results made it possible to predict the behaviour of different coals with a high amount of accuracy. This work yielded a thesis, for which she received her Ph.D. in 1945.
After the war Franklin went to France, getting a position in the lab of Jacques Mering where she learned the technique of X-ray crystallography. X-ray crystallography is a technique in which the atomic structure of a substance by subjecting it to X-ray bombardment. The X-ray photons are diffracted by the substance and are detected by a photographic plate. The atomic structure of the substance being investigated can be determined by measuring the angles of diffraction. Franklin applied used this technique to continue her studies of carbon structure. Franklin liked the intellectual and egalitarian nature of French culture, preferring it to the middle class English customs of her upbringing.
In 1950 Franklin returned to England to work in the lab of John T. Randall at Kings College London. She was assigned to work with Maurice Wilkins to use X-ray crystallography to study DNA. The much less collegial atmosphere at Kings College did not suit Franklin and she and Wilkins did not communicate. Franklin worked on her own, with graduate student Raymond Gosling, taking increasingly clear pictures of DNA. From her pictures she realized that DNA could assume two different structures, which she labeled A and B. The A form is seen in drier conditions than the B form, the B form being the form that is found en-vivo. Previous researchers had been unable to determine an exact structure because they had been analyzing a mixture of the two forms.
Unknown to Franklin, Wilkins showed one of her diffraction photographs to Francis Crick and James Watson who were at Cambridge also working to determine the structure of DNA. The photograph provided crucial information that allowed them to publish their structure for DNA in 1953. Although they remained cordial with Franklin, Watson and Crick never fully acknowledged the help they received from Franklin in determining their structure.
Unhappy working at Kings College, Franklin arranged to transfer her fellowship to work at the crystallography laboratory of J.D. Bernal at Birkbeck College. There Franklin used her skill with X-ray crystallography to study viruses, particularly the tobacco mosaic virus (TMV) and determined that the virus' genetic material (RNA in the case of TMC) is embedded in the inner wall of its protein shell. In the Fall of 1956 Franklin was diagnosed with ovarian cancer. She died on April 16, 1958.
Elkin, Lynne Osman; "Rosalind Franklin and the Double Helix"; Physics Today (2003)56:42-48
Maddox, Brendal; Rosalind Franklin: The Dark Lady of DNA
; Harper Collins; 2003
The Rosalind Frankin Papers at profiles.nlm.nih.gov