Rosalind Franklin's first important contributions to the model popularised by Crick and Watson was her lecture at the seminar in November 1951, where she presented to those present, among them Watson, the two forms of the molecule, type A and type B, her position being that the phosphate units are located in the external part of the molecule. She also specified the amount of water to be found in the molecule in accordance with other parts of it, data that have considerable importance in terms of the stability of the molecule. Franklin was the first to discover and formulate these facts, which in fact constituted the basis for all later attempts to build a model of the molecule. However, Watson, at the time ignorant of the chemistry, failed to comprehend the crucial information, and this led to construction of a wrong model.
The other contribution included an X-ray photograph of B-DNA (called Photo 51), that was briefly shown to Watson by Wilkins in January 1953, and a report written for an MRC biophysics committee visit to King's in December 1952 which was shown by Perutz at the Cavendish Laboratory to both Crick and Watson. This MRC report contained data from the King's group, including some of Franklin's and Gosling's work, and was given to Crick – who was working on his thesis on haemoglobin structure – by his thesis supervisor Perutz, a member of the visiting committee.
Sayre's biography of Franklin contains a story alleging that the photograph 51 in question was shown to Watson by Wilkins without Franklin's permission, and that this constituted a case of bad science ethics. Others dispute this story, asserting that Wilkins had been given photograph 51 by Franklin's Ph.D. student Gosling because she was leaving King's to work at Birkbeck, and there was allegedly nothing untoward in this transfer of data to Wilkins because Director Randall had insisted that all DNA work belonged exclusively to King's and had instructed Franklin in a letter to even stop working on it and submit her data. Also, it was implied by Horace Freeland Judson, that Maurice Wilkins had taken the photograph out of Franklin's drawer, but this is also said to be incorrect.
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