The Forgotten Face Behind the Double Helix

Описание: Source- PMID 32730810

Rosalind Franklin created Photo 51 through meticulous expertise in X-ray crystallography while working at King’s College London in the early 1950s. She prepared extremely pure, well-oriented fibres of DNA and exposed them to a finely tuned beam of X-rays. By controlling humidity, temperature, and the structure of the DNA fibres, she was able to coax the molecule into its “B-form,” the version that reveals the most detailed pattern. When the X-rays diffracted off the atoms inside the DNA, they produced an image on photographic film, a striking X-shaped pattern that became known as Photo 51. The image was extraordinary because it provided clear, direct evidence that DNA had a helical structure. The sharp cross shape, spacing of the bands, and overall symmetry contained the mathematical clues needed to work out the double helix’s dimensions. Franklin’s precision and scientific rigor were essential; without her careful sample preparation and expert handling of the X-ray equipment, Photo 51 would never have been captured with such clarity. It remains one of the most important photographs in the history of science.

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