The 1962 Nobel Prize in Physiology or Medicine was awarded to Francis Crick, James Watson and Maurice Wilkins, recognizing their work in discovering the structure of DNA. Not included in the Prize was Rosalind Franklin, a scientist whose research made essential contributions to the Nobel Prize winners understanding of DNA.

A research scientist at King’s College London with expertise in X-ray imaging (referred to as X-ray crystallography or X-ray diffraction), Franklin’s contributions included key images of DNA, taken with these imaging techniques. X-ray crystallography allows analysis of atomic structures not visible with traditional light microscopy. Through these images, Franklin realized that she was seeing two forms of DNA. In a 1953 paper published with Raymond Gosling, a doctoral student she was supervising, she named these forms A- and B-DNA, names we still use today.

One notable image of B-DNA was the iconic photo 51. This image of DNA was captured by Gosling in 1952 and gave unique insight into the structure of this form of DNA. In B-DNA, the type of DNA most commonly found in our bodies, the base pairs – the parts of DNA whose order enables DNA to contain its code of information – project consistently into the center of the molecule at angles almost perpendicular to the overall direction of the outer part of the molecule. Photo 51 created critical evidence for this aspect of B-DNA structure.

Wilkins was another research scientist with expertise in X-ray imaging who worked at King’s College London. As Franklin was preparing to leave King’s College London, Wilkins became Gosling’s doctoral advisor and therefore saw photo 51. He then shared this image with Crick and Watson who recognized it as evidence for the structure of B-DNA. They were then able to finalize their molecular model of DNA that would eventually lead them to win the coveted Nobel Prize.

Franklin published five papers in three years specifically on her work with DNA at King’s College London, but published dozens of papers describing her research work in other labs during her career. Other projects included work with viruses where she imaged RNA, another nucleic acid, and earlier in her career she analyzed carbons, for example in the form of coal. Franklin died in 1958 at the age of 37, after living with ovarian cancer for almost two years.

Her work with DNA and time at King’s College London was critically important, however, her body of work expanded scientific knowledge throughout her robust yet short career. When we celebrate Franklin’s work on DNA, we can also celebrate her as a person. There is no better day to celebrate her than July 25, her birthday. Happy 99th birthday to Rosalind Franklin, July 25 1920 – April 16 1958.