Rosalind Franklin and the DNA double helix

Rosalind Franklin is probably best known as the woman behind the discovery of the DNA double helix, but she did not immediately receive that recognition. In 1962, James Watson, Francis Crick and Maurice Wilkins received the Nobel Prize for uncovering the structure of DNA, which was based on Franklin’s work.

Rosalind Franklin died four years before the Nobel was granted to the three men who contemplated “Photograph 51.” She lived a short, but scientifically full, 37 years. She had a PhD in physical chemistry from Cambridge University, laying the groundwork for understanding carbon fibers in her studies of efficient coal use. After learning X-ray crystallography in Paris, she worked at Kings College in London where she fine-tuned an X-ray machine capable of crystallographic imaging. X-ray crystallography was a new science that Franklin pioneered in work on large, complex biological molecules. She used it to image DNA in attempts to determine the structure of hereditary material, something that had been elusive for nearly a century. She worked with Maurice Wilkins, with whom she had well known friction. His competition with Watson and Crick, as well as the anti-female sentiment in science at the time, has led to the belief that the three men used Franklin’s work without her permission, without Wilkins even acknowledging her contributions in his lab at the time.

Franklin’s crystallographic photographs of DNA are some of the most famous images in science, especially genetics. For the first time she captured the double helical shape of B-DNA, the most common naturally occurring alignment of double-stranded deoxyribonucleic acid. The images each took 100 hours of X-ray exposure. At Kings College, Wilkins shared Franklin’s photographs, including famous photograph 51 taken in 1952, with Watson and Crick at Cambridge, and the two now famous men ultimately won the race to publish their proposed structure of DNA in 1953. Franklin had to seek another position and was required by the president of the school to not work on DNA – so she moved on to laying the foundation for the field of structural virology before her untimely death from cancer.

Though Rosalind Franklin has been discounted as a lab tech over the years, which for some justified her exclusion from the history of DNA discovery, evidence exists that she did offer insight into her crystallography images. She was the first to recognize that DNA exists in more than one form – and ultimately was the one who discovered B-DNA. She also discerned that the structure must have phosphates on the backbone. Also, some quote her as recognizing the double helical structure before Wilkins, Watson or Crick ever saw the photographs.

In addition to the double helix, Franklin made strides in viral genetics. She was working on tobacco mosaic virus, a plant pathogen that can affect tobacco crops, when she died. Her educated conclusion that its genome was a single stranded RNA helix was confirmed posthumously – just one more discovery in genetics that she didn’t get to see her name put to.

Though she was trained as a physicist and chemist, Rosalind Franklin’s work led to one of the greatest discoveries in the history of genetics, which continues to affect the world today.