Rosalind Franklin

Originally intended as an insult by a coworker, Rosalind Franklin’s title “Dark Lady of DNA” now stands as a testament to her profound impact on science. Best known for her pivotal contributions to uncovering the structure of DNA, Franklin’s work ranks among the 20th century’s most significant biological discoveries. Beyond DNA, she also advanced the knowledge of virus structure, setting the groundwork for the field of structural virology.

Rosalind Franklin was born on July 25, 1920, in the Notting Hill neighborhood of London, England, into a prominent British Jewish family. Her father, Ellis Franklin, who taught magnetism and electricity at the Working Men’s College of London, was a strong advocate for his daughter’s scientific education. 

Rosalind was always drawn to facts, valuing logic and precision, and she developed a keen interest in science from a young age. At 15, she decided to pursue a career in science, and by 18, she had passed the admission examination for Cambridge University. However, this achievement sparked a family crisis as her father initially opposed university education for women and refused to fund her education. Her aunt intervened, insisting that Rosalind should pursue her education and offering to pay for it. Her mother also supported her, and ultimately, her father relented.

After graduating in 1941, Rosalind Franklin received a fellowship to conduct research in physical chemistry at Cambridge. However, the onset of World War II altered her career path. Not only did she serve as an air raid warden in London, but in 1942, she also left her fellowship to join the British Coal Utilisation Research Association. There, she focused on the physical chemistry of carbon and coal to support the war effort, as coal was a crucial fuel source for Britain during the war.

Franklin’s work involved classifying types of coal and linking these classifications to their efficiency as fuel, based on their porosity, much like a sponge’s, and the size of their internal tunnels. She made a groundbreaking discovery that the pores in coal were about the same size as gas molecules, enabling coal to act as a molecular sieve for separating different molecules. This principle of using carbon-based molecular sieves has since been applied in various technologies, including the extraction of oxygen from air.

By the age of 26, Rosalind Franklin had earned her PhD, and with the end of the war, she shifted her focus to X-ray diffraction. This technique involves reflecting X-rays off crystals to determine their structure and composition. Franklin was a pioneer in applying this method to complex, unorganized materials, such as large biological molecules, not just single crystals.

She spent three years in France, where she enjoyed the work environment, the freedoms of peacetime, and the French food and culture. However, in late 1951, she returned to London to work as a research associate at King’s College. By the end of that year, she and her assistant, Raymond Gosling, had discovered that DNA could exist in two forms: as a thin fiber in relatively high humidity, known as A-DNA, or in a compact, “crystalline” form in dry conditions, known as B-DNA. While the exact shape of A-DNA remained unclear, the research team conclusively determined that B-DNA was a helix. Notably, Franklin’s famous Photo 51, captured in 1952, depicted B-DNA, marking a significant advance in understanding DNA’s structure.

Before the discovery of DNA’s structure, no one could comprehend how a simple molecule like DNA could store vast amounts of information. The double-helix model provided the answer, showing that DNA encodes information in the sequences of base pairs within the helix and replicates this information by separating the helical strands and recreating the matching strand.

At the time, however, Rosalind Franklin was not as captivated by Photo 51 as her assistant, Raymond Gosling. Her focus remained on solving the structure of A-DNA, and she was also on the verge of leaving King’s College. 

Consequently, Gosling was reassigned to a new supervisor, Maurice Wilkins. Without Franklin’s consent, Gosling shared her research with Wilkins, who then presented it to James Watson and Francis Crick at Cambridge University. Watson, who had also been exploring DNA’s structure, recognized the importance of Photo 51 immediately. In his 1968 book, “The Double Helix,” he recounted his reaction: “The instant I saw the picture my mouth fell open and my pulse began to race.”

On April 25, 1953, James Watson and Francis Crick published a landmark paper in Nature, unveiling the double helix as DNA’s structure. In the concluding paragraph, they acknowledged the influence of “the general nature of the unpublished experimental results and ideas” from Maurice Wilkins and Rosalind Franklin at King’s College London. Nine years later, Watson, Crick, and Wilkins were awarded the Nobel Prize in Physiology or Medicine. A year before the Nobel, Crick acknowledged in a letter that “the data which really helped us to obtain the structure was mainly obtained by Rosalind Franklin.”

The restrictions at King’s College, including the ban on women scientists from the men’s lunchroom, and her tense relationship with Wilkins, motivated Franklin to leave. In 1953, she accepted a position at Birkbeck College in London, shifting her focus to RNA due to a condition from King’s College that prohibited her from continuing DNA research.

At Birkbeck, Franklin employed X-ray crystallography to investigate RNA viruses, including the tobacco mosaic virus. This work later led her to research the structure of the polio virus. During a professional trip to the United States, Franklin experienced episodes of pain, which were diagnosed as ovarian cancer. Despite undergoing three operations and experimental chemotherapy, and experiencing a 10-month remission, she continued her work tirelessly until just a few weeks before her death in 1958 at age 37. Her research team ultimately determined that the polio molecule has icosahedral symmetry, resembling a 60-sided soccer ball. Sadly, Franklin did not live to see these findings published.

Franklin’s discoveries have profoundly influenced our understanding of DNA, RNA, and polio. Her pioneering work remains a source of inspiration worldwide. In 2004, the Rosalind Franklin University of Medicine and Science in Chicago was renamed in her honor.