(By Dr Helen Robertson.)
Prior to 2020, genetic mutations weren't something that regularly made the news. Now, two-and-a-half years out from the onset of the COVID-19 pandemic, new genetic variants continue to hit the headlines, and genomic mutations – in a virus, at least – are something the public are much more aware of. But with the constantly evolving COVID-19 virus (Omicron BA.5, I'm looking at you), it's interesting to think about where genomes might have come from in the first place. In Why DNA? From DNA Sequence to Biological Complexity, Professor Andrew Travers charts the biochemical story of DNA as a tool for information transmission, and how the properties of DNA have led to the diversity of life and the ecosystem interactions we see in nature.
Firstly, this book is not for the scientifically faint-hearted. The biochemistry and physics detail of the book – particularly in the early chapters – is dense, and this book is not written for someone who is looking for an entry-level introduction to DNA and biological information transmission. Despite some analogies and comparisons to more recognisable concepts, Why DNA? is better suited as a companion book to undergraduate courses or current and prospective researchers, not as a piece of popular science.
The early chapters of the book are a real deep dive into the biochemistry of biological information. Admittedly, I found the many references to the laws of physics and technology in the early part of the book a little heavy, but I recognise that this perhaps speaks more to my scientific interests than the scope of the book.
By Chapter 3, which focused on DNA as a molecule for information storage and transmission, I was in more familiar territory, and was particularly interested by the section discussing mechanisms employed by DNA to withstand even extreme temperature changes, and the necessary shift from circular to linear chromosomes as a means of increasing information storage. I think this exemplifies the breadth of information covered in the early parts of the book: it's a whistle-stop tour from early forms of life using an RNA code to the specification of amino acids to the mechanism of DNA coiling. These are certainly interesting concepts, but the density of quite complex information presented here doesn't make these early chapters an easy read.
For me, the more engaging and interesting parts of this book were in the later chapters. A concept that I enjoyed reading about was the evolution of biological complexity. I am not particularly familiar with the consequences of cellular environment on metabolic pathways, so I enjoyed reading about the early hydrothermal vent environment that might have permitted the chemical reactions leading to the origins of life.
Further, Professor Travers also wrote about the role of genomic organisation in the specification of cell types and body plans. Although I have worked on this in my own research, the examples in this section are much more accessible (and, I think, more interesting!). It is perhaps surprising that the average genome of a flowering plant contains five-ten times more DNA than the genome of an animal, given that the average animal has many more types of cells specialised for different roles than that of a plant. But much like the earlier chapters, these real-world examples seem to get lost in the density of information – perhaps that's because of its intended audience, but I would have enjoyed more discussion around these types of case studies.
It goes without saying that Professor Andrew Travers writes with huge expertise: as an emeritus scientist at the MRC Laboratory of Molecular Biology, University of Cambridge, and a previous student of Dr James Watson himself – who was awarded a Nobel Prize for his discovery of the double helix structure of DNA in 1962 alongside Professors' Francis Crick and Maurice Wilkins – he is very well placed to write on DNA and genomic evolution.
His knowledge across the breadth of this subject is evident from the contents of the book, and for scientists with an interest and prior knowledge of molecular biology and biological information this book would make an excellent companion to your studies or research. Certainly, a reasonable grounding in science is necessary to engage with and enjoy the book, and for me, writing more widely on interesting examples while narrowing the scope of the book would have made for a more dynamic read. However, if you are looking for a book to fill the gaps in your knowledge around DNA, this is a very comprehensive option.