Unravelling DNA’s structure: a landmark achievement whose authors were not fairly credited

The Conversation
April 28, 2023

Digital illustration of DNA (Shutterstock.com)

Seventy years ago, two male scientists, Francis Crick and James Watson, proclaimed they had discovered the secret of life: the structure of DNA. Since then, history has acknowledged how Rosalind Franklin was sidelined. But new archive evidence has cast doubt on the widely accepted narrative – that Franklin collected an all-important image but didn’t appreciate the meaning of what she was looking at.

This knowledge of DNA allowed for a deeper understanding of how DNA stores information and how it is replicated. It led to technologies such as DNA fingerprinting, gene sequencing, gene editing and personalized medicines.

For most of the past 70 years the names Watson and Crick have been synonymous with DNA. But scientific discoveries are rarely the result of a few individuals. Most breakthroughs happen through collaboration. The story of DNA is no exception.

The structure of DNA discovery was actually described in a series of three papers. And the three papers were the result of direct input from seven authors: Rosalind Franklin, Raymond Gosling, Maurice Wilkins, Alec Stokes, Herbert Wilson, James Watson and Francis Crick.

Nevertheless she persisted

Franklin suffered dreadfully from the endemic sexism of the time. In Watson’s 1968 book The Double Helix he frequently disparages Franklin, making negative comments about her appearance, her feminist principles and her emotions. In one passage Watson writes: “Given her belligerent moods, it would be difficult for Maurice Wilkins to maintain a dominant position that would allow him to think unhindered about DNA.”

Franklin, along with her PhD student Raymond Gosling, created one of the most famous images in science. It was a photograph generated by shining x-rays through a crystal of DNA, using a technique called x-ray crystallography. The image is known as Photo 51, and it contained critical information on the physical dimensions of DNA.

Rosalind Franklin. 1955. From the personal collection of Jenifer Glynn

The story goes that the image was shown to Watson, without Franklin’s knowledge or permission. In his book Watson tells how seeing the image triggered a eureka moment, during which the helical structure of DNA became obvious to him. This narrative (which has been retold by popular articles and a stage play featuring Nicole Kidman) portrays Franklin as a victim of intellectual property theft, but implies she did not understand the implications of her data. Given Franklin was a skilled X-ray crystallographer while Watson was a relative newcomer to the field, this seems unlikely.




Photo 51: X-ray diffraction image of the double helix structure of the DNA molecule, taken in 1952 by Raymond Gosling \ Raymond Gosling/King's College London

While researching biographies on Watson and Crick, Matthew Cobb (professor of zoology) and Nathaniel Comfort (professor of the history of medicine) unearthed a draft news article for Time magazine from 1953, never published, which hints at a different set of events. A description of the article and other newly discovered letters was published in the journal Nature, 70 years to the day after the original DNA papers appeared in the same journal.

Things could have been different

The draft news article, written in consultation with Franklin, portrays the DNA work as being carried out through an equal collaboration between two teams. One based in King College London, which included Wilkins and Franklin. The other in the Cavendish laboratories, Cambridge, comprised of Watson and Crick. The London team collected experimental data, whilst the Cambridge duo used the information to build a structural model.

The article describes an exchange of information, including Franklin “checking the Cavendish model against her own x-rays’ data”. In this narrative Franklin is an equal member of a group of four leading scientists. Cobb and Comfort speculate that Franklin probably wasn’t happy with the way the science in the Time draft was communicated, and so it never made it to press.

Unlocking the role of DNA

Given what we now know about DNA’s central role in biology it is difficult to imagine a time when we did not credit it with carrying our genetic blueprints. However, scientists used to think proteins were responsible.

Changing this view was crucial. Without an understanding of DNA’s role in biology Watson and Crick would not have been at all interested in DNA.

Another overlooked voice is that of Florence Bell. In 1939 she was a PhD student at the University of Leeds, a position that was so unusual that when Bell presented her work at a conference, the Yorkshire Evening News ran an article with the headline “Woman scientist explains”.

She produced the first x-ray images of DNA. The images were lower resolution than those made by the King College team. However they did reveal DNA’s regular structure and provided key dimensions of the molecule. Bell’s work also gave her an inkling of DNA’s critical role in biology. In her PhD thesis she wrote, “the beginnings of life are closely associated with the interaction of proteins and nucleic acids.”

The experiment that settled the debate was performed by Alfred Hershey and Martha Chase in 1952. They used bacteriophages, viruses that infect bacteria, to show that DNA, not proteins, carried genetic information.

When Hershey died in 1997, James Watson penned a memorial article in which he wrote “the Hershey-Chase experiment … made me ever more certain that finding the three-dimensional structure of DNA was biology’s next important objective.”

Taking the credit

Unlike their male colleagues, neither Franklin, Chase nor Bell reaped the benefits of their groundbreaking science. Hershey, Watson, Crick, and Wilkins all received Nobel prizes. The male authors of the 1953 DNA paper enjoyed long careers in academia. But Chase only had a brief spell as a researcher before losing her job, for reasons that are unclear. Bell married a US serviceman and emigrated to the US. Florence Bell died in 2000, Martha Chase in 2003. Their deaths went largely unnoticed.

Franklin’s achievements were cut short by her death from ovarian cancer in 1958 at the age of 37.

Franklin, Bell and Chase are far from the only women whose contributions to science are underappreciated. In the 1940s, Margaret Hutchinson Rousseau designed the first commercial penicillin production plant. Working in her kitchen in 1891 Agnes Pockels worked out fundamental principles of how soaps behave. And Elizabeth Fulhame introduced to science the concept of catalysis, 40 years before its “discovery” by Jons Jakob Berzelius in 1835.

Much has changed since 1953. However, women are still massively underrepresented in the higher echelons of science. Much more is still to be done.

Mark Lorch, Professor of Science Communication and Chemistry, University of Hull

This article is republished from The Conversation under a Creative Commons license. Read the original article.