By Holly Giles | Deputy Editor
The double helix structure of DNA has become an image synonymous with science all over the world and few people would not recognise it today. However, this structure was only discovered in the 50s and has revolutionised the field ever since. Two of the biggest names associated with its discovery are those of Watson and Crick but their conclusion relied on the work of Rosalind Franklin, who is arguably one of the most unsung heroes of science.
Rosalind Franklin was born in 1920 in London where she grew up. She studied physics and chemistry at Cambridge University. She initially worked for the British Coal Utilisation Research Association, where she completed her Ph.D., but then moved to Paris where she learnt imaging techniques which she went on to use at King’s College in her work on DNA.
At King’s College Franklin was working on discovering the structure of DNA and performed a series of experiments to deduce its helical arrangement. She created an image of her current findings, called “photo 51”. Despite being unpublished the image was shown to Watson by a previous colleague. The pattern in the image was clearly a helix and it was this inspiration that led Watson and Crick to arrive at the final double helix structure that is so widely accepted today. Whilst there was still a lot of work to do by the pair, including the precise distance of the elements of DNA, the dimensions and the angle of the helix, her image was the foundation of their work and was paramount to their success. Perhaps the most shocking of all is the finding that Crick and Watson did not ask Franklin for permission to interpret her data, or to use her image, and did not inform anyone at King’s College what they were doing.
In 1953 Franklin was invited to Cambridge to see the proposed model for the structure of DNA made by Watson and Crick. They all immediately agreed that the double-helix arrangement must be right. After this it was agreed that the model would be published solely under the name of Watson and Crick, with supporting data being published separately by Franklin and her colleague Wilkins. The articles were both published in Nature. This separation of articles seconds the separation of her work from Watson and Crick’s which was far from an accurate image of the scene.
Franklin was overlooked, especially in the Nobel prize won by Watson and Crick in 1962 which made no mention of her contribution. It was only after her death that Crick acknowledged her work as a critical contribution. As explained by The Guardian, “her conceptual understanding of the structure of the DNA molecule and its significance was on a par with that of Watson and Crick, while her crystallographic data were as good, if not better, than those of Wilkins”.
Whilst it is the most famous moment of her career, after discovering the structure of DNA, Franklin then went on to investigate the structure of viruses and laying much of the foundation for virology methods used today. In her work into the tobacco mosaic virus (which was ironically previously studied by Watson before he turned his attention to DNA) she found that RNA was the central component of the virus, rather than DNA, and that this was arranged in a single helix instead.
Over time, building on the initial structure devised by Franklin, Wilkins, Watson and Crick, scientific knowledge of DNA has increased to a point where we can now use it for a wide variety of purposes. DNA can be used to identify people in crime, to track our ancestors, diagnose diseases and many more. One of the most recent developments in DNA is our ability to manipulate and edit DNA through CRISPR technology.
CRISPR has a specific target sequence which it is able to find in the DNA and attach to it, before altering that piece of DNA, either by switching a base (a letter of the DNA code), adding a segment or deleting a segment. This allows genes to be added, removed, switched on or switched off.
The implications of CRISPR are huge and the ability to edit DNA opens up the opportunity of so-called “designer babies”. This started with Chinese researcher He Jiankui editing genes of a human embryo in a lab dish in 2015, and despite causing worldwide controversy, has been continuing ever since. According to Chinese medical documents released in 2018 the team recruited couples to create the first gene-edited babies. They plan to eliminate the CCR5 gene in the hopes of making the child resistant to HIV, smallpox and cholera. In one of the consent forms signed by the parents Jiankui claimed “this technique may be able to produce an IVF baby naturally immunised against AIDS”.
Twin girls named Lulu and Nana (to protect their identities) were born through this experiment in 2019 but there is no current data confirming the change to the children’s DNA. There are worries that this genome editing may have affected their DNA at other regions and could make them more susceptible to other conditions. This would have put the children at unnecessary risks so opens up a group of ethical research problems surrounding minimising harm. There is now a legal investigation into the work of He Jiankui, who is thought to have broken multiple laws surrounding the ethics of this experiment. The investigations are ongoing into Jiankui as well as looking at other scientists who are suspected to know more about the work, referred to as those in his “circle of trust”.
Whilst this may seem like a great achievement for science in the possible prevention of disease, it is a slippery slope to parents selecting traits and features they deem as desirable. It means the prospect of designer babies is both possible and not far from our reach. Some scientists suggest this change is inevitable, as shown in the statement by CRISPR researcher Jennifer Doudna:
“To me, the question now is, ‘How will it happen? How do we control, or can we even control it in any reasonable sense of that word? And what will the impact be on society going forward?’”
It is not known what is currently happening to Lulu and Nana, or if there are other children born through the experiment. This work shows how far scientific knowledge has advanced from Franklin first realising the structure of DNA only 60 years ago. We are advancing at an exponential rate and one that law cannot keep up with. Designer babies are on the horizon and it calls into question, if them, then what next?