Franklin's X-Ray Crystallography Experiments
Regular substances like crystals diffract X-rays in characteristic patterns according to their physical structure. The X-ray crytallograph at right ("Photo 51") shows the diffraction pattern of a crystallized DNA molecule. The cross pattern in the middle is characteristic of a helical molecule with regular repeats; the broad bands at top and bottom give an indication of the periodicity of the repeats. The photograph is of the highly hydrated B form of DNA, rather than the drier A form, which does not show a distinct helical structure.
Rosalind Franklin (1920 -
1958), whose grad student Raymond Gosling (1926 - ) made
the photograph, worked as a post-doctoral researcher in the same
lab as Maurice Wilkins,
and approached the structure of DNA as a physical
problem in crystalline structure. Opinion and evidence vary as
to how and when she interpreted her evidence as bearing on the
helical nature of the molecule.
& Wilkins subsequently received the Nobel Prize in
1962 for solving the structure of DNA. By the time of
the award, Franklin was dead: the Nobel is not awarded
posthumously, nor to more than three persons. Watson's
autobiographic account of the discovery of "The Double Helix" (1968)
paints an unflattering personal portrait of Franklin, and was
widely criticized at the time and subsequently as inaccurate and
sexist. Watson and Crick repeatedly acknowledged that they could
not have solved the structure without Franklin's evidence
Priority of discovery, acknowledgement of ideas, and ownership
of data continue to be controversial topics in science. The
story of the discovery of DNA structure is an
exceptionally well-documented one. From the evidence and
statements of participants, consider the following statements
1) Watson and Crick ripped off Franklin, who was badly treated because she was a woman.
2) Whose property is Photo 51, and who was entitled to see it?
3) "Grad students in those days were treated like serfs."
4) "She was definitely anti-helical."
5) I showed them pairing, I wasn't properly acknowledged