This article was first published in May in our exclusive members’ newsletter, My Mensa Weekly.

Words: Joanna Cummings

DNA may be “the secret of life”, but it has also been the source of much controversy over the last 70 years – or at least, its discovery has. 

Seventy years ago, on 28 February, James Watson and Francis Crick walked into The Eagle pub in Cambridge with a big announcement: they had determined the double helix structure of DNA. Or in their words, they had “discovered the secret of life”.  

However, a little later, a new narrative took shape: that James Watson had ‘taken’ the X-ray crystallography confirming its structure from a certain Rosalind Franklin, who was leading a rival study team. After that, it transpired that one of Franklin’s students – Raymond Gosling – had actually prepared the X-ray.   

Nowadays, the parts of each of the various protagonists are more likely to be acknowledged (see DNA: The milestones below) but the day the double helix structure was discovered is still considered the most important day in the calendar. In fact, many believe – as did science writer and journalist Matt Ridley in The Spectator – that 28th February 1953 was “the most important day in the history of science”. 

What is DNA, and why is it important? 

DNA, or deoxyribonucleic acid, is a complex molecular structure found inside the cells of all forms of life. It is formed of two coiled antiparallel strands known as polynucleotides; each strand comprises nucleotide base pairs of adenine (A) plus thymine (T), and guanine (G) plus cytosine (C). (Note: a combination of these four letters made up the name of the 1998 film about eugenics, Gattaca). 

DNA contains all the molecular information to allow transmission of inherited traits. Enzymes transcribe this information into mRNA, an intermediary molecule, which in turn is translated into the amino acid ‘language’. This allows the production of proteins. 

The structure of DNA is significant, as it enables it to replicate itself for cell division, or ‘mitosis’ – this being crucial for the development of embryos, and the production and replacement of cells in our own bodies. During mitosis, DNA splits into two single strands, which serve as templates for new double strands – adenine being added wherever there is thymine, guanine to cytosine, and so on. 

To say that our growing understanding of DNA has had a huge impact on our lives is an understatement. It has led to the development of genetic testing, allowing the medical profession to identify hereditary conditions. It has helped us to understand everything from child development to how we age, from agriculture to animal conservation. 

It has significantly driven forward the field of forensic science, allowing the tracing of criminals and the identification of human remains. Its ability to determine accurate parentage has caused disputes in many family units across the world – as well as on tabloid talk shows and in innumerable soap opera episodes. 

A warning to the curious 

The impact of DNA – and its modification or manipulation – on popular culture doesn’t stop there. Understandably, the significance of DNA has captured the imagination of fiction writers and film makers too. From Blade Runner to The Boys from Brazil, we have been warned many times about the (usually disastrous) impacts of genetic engineering… though it is Jurassic Park – where newly discovered dinosaur DNA is mixed with that of sex-changing frogs to create a theme park-zoo – that has arguably caused the most childhood nightmares. 

Thankfully, the techniques employed in science fiction require substantial suspension of disbelief –given that dinosaur DNA has never been found (and is unlikely to be, given the speed of DNA degradation), the chances of finding a velociraptor in your kitchen are slim. 

And there are actually many benefits to the ethical applications of DNA-based science. For example, the development of stem cell technology could provide solutions for infertility and help in the treatment of cancer. It could help us prevent animal extinction and mitigate global warming. It has told us – and could tell us so much more – about our own evolution. 

We’ll never know if the pub-goers in 1953 Cambridge drank a toast to Crick and Watson. But I hope that here in 2023, you’ll join us in raising a glass to them, and to everyone who has played a part in expanding our knowledge of DNA.