History of molecular biology Crick and Watson built physical models using metal rods and balls, in which they incorporated the known chemical structures of the nucleotides, as well as the known position of the linkages joining one nucleotide to the next along the polymer. At King's College Maurice Wilkins and Rosalind Franklin examined X-ray diffraction patterns of DNA fibers. Of the three groups, only the London group was able to produce good quality diffraction patterns and thus produce sufficient quantitative data about the structure. In 1948 Pauling discovered that many proteins included helical (see alpha helix) shapes. Pauling had deduced this structure from X-ray
Maurice Wilkins Raymond [Gosling] and I got a clear crystalline X-ray pattern I was very eager to continue that work ... Trying to understand 'what really happened' when a very admirable scientist [Randall] models himself on Napoleon is not easy ... [but the letter] was very damaging to her and to me". By November 1951, Wilkins had evidence that DNA in cells as well as purified DNA had a helical structure. Alex Stokes had solved the basic mathematics of helical diffraction theory and thought that Wilkins's X-ray diffraction data indicated a helical structure in DNA. Wilkins met with Watson and Crick and