Skip to main content

Junk DNA - Nessa Carey ****

What grabs the reader fairly early on in Junk DNA is just how wonderfully complex and sophisticated the biological machinery in our cells is. As a non-biologist, I found that reading her description of the way that the cellular mechanisms pull the two copies of a chromosome to opposite sides of the cell, for instance, absolutely riveting. But it's not all superbly functioning miniature marvels: Nessa Carey also explores the many ways that these genetic mechanisms can go wrong. Anyone who ascribes the complexity of biological systems to a designer needs to contemplate just what a messy, over-complex and ad-hoc design has emerged.

I really hadn't though of there being a mechanism for separating copies of chromosomes before - and I think this is the beauty of Carey's book. Us non-biologists have some vague idea of how cells split or proteins are assembled from the genetic 'instructions', but there's a whole host of mechanisms required to go from an apparently simple concept to making it happen, and this really opens up in Junk DNA.

I mentioned how things go wrong. As genetic medical conditions are often a key to unlocking the secret of a cellular mechanism, there is a lot about genetic failures here, some very distressing - I'm personally not a great enthusiast for things medical (I can't even watch Casualty, let alone 24 Hours in A&E), but in this context it at least wasn't gratuitous.

Of course, as the name suggests, at the heart of the book are all the bits of our DNA - the vast majority of the content of our chromosomes - that aren't genes. In her previous book, The Epigenetics Revolution, Carey had already introduced us to some of the workings of what was once referred to as 'junk DNA' - specifically how parts of it turn various genes on and off, effectively acting as the controls that work the mechanisms specified by our genetic blueprints - but in this new book we see many more processes, capabilities, wonders and failings of the super-genetic parts of the system.

I do have a couple of niggles. This is a topic that lends itself to metaphor and simile - I did it without even noticing in the previous paragraph, but Carey plunges into metaphorical mode at the slightest opportunity, and some of her similes are a little painful - when she brings in the movie Trading Places or a Bugatti Veyron, for instance, the process seems forced. (Even the subtitle is a metaphor of sorts.) Also slightly irritatingly, several times she refers to the human appendix as having no function - if she'd read my Universe Inside You, she'd have known that this concept, like classifying all DNA that doesn't code for proteins as junk, went out some time ago (the appendix does have a useful function as a kind of respite centre for friendly bacteria from the wild conditions in the stomach).

The other issue, which I also referred to in my review of The Epigenetics Revolution, and similar to the complaint I had about I, Superorganism is that we end up in Rutherford's 'all science is either physics or stamp collecting' territory. While some the mechanisms themselves are truly fascinating, when the reader gets bogged down in the detail it can begin to seem that there is far too much cataloguing and not enough narrative. Carey has usefully responded to reviews of the previous book by often moving the name of a gene into a footnote, but it doesn't prevent the feeling of drowning in labels when you read something like:
Where C is followed by G in our genome, the C can have a small modification added to it. This is most likely to happen in regions where this CG motif is present in high concentrations. The large number of CCG repeats in the Fragile X expansion provide exactly this environment.
This is by no means the most concentrated example of labellitis, and typical of quite a lot of the text. In the end I was happy to think 'It goes with the territory, live with it.' There is still so much fascinating material in here that it is well worth ploughing through the biological wordfest.

Review by Brian Clegg


Popular posts from this blog

Astrophysics for People in a Hurry – Neil deGrasse Tyson *****

When I reviewed James Binney’s Astrophysics: A Very Short Introduction earlier this year, I observed that the very word ‘astrophysics’ in a book’s title is liable to deter many readers from buying it. As a former astrophysicist myself, I’ve never really understood why it’s considered such a scary word, but that’s the way it is. So I was pleasantly surprised to learn, from Wikipedia, that this new book by Neil deGrasse Tyson ‘topped The New York Times non-fiction bestseller list for four weeks in the middle of 2017’.

Like James Binney, Tyson is a professional astrophysicist with a string of research papers to his name – but he’s also one of America’s top science popularisers, and that’s the hat he’s wearing in this book. While Binney addresses an already-physics-literate audience, Tyson sets his sights on a much wider readership. It’s actually very brave – and honest – of him to give physics such prominent billing; the book could easily have been given a more reader-friendly title such …

Once upon and Algorithm - Martin Erwig ***

I've been itching to start reading this book for some time, as the premise was so intriguing - to inform the reader about computer science and algorithms using stories as analogies to understand the process.

This is exactly what Martin Erwig does, starting (as the cover suggests) with Hansel and Gretel, and then bringing in Sherlock Holmes (and particularly The Hound of the Baskervilles), Indiana Jones, the song 'Over the Rainbow' (more on that in a moment), Groundhog Day, Back to the Future and Harry Potter.

The idea is to show how some aspect of the story - in the case of Hansel and Gretel, laying a trail of stones/breadcrumbs, then attempting to follow them home - can be seen as a kind of algorithm or computation and gradually adding in computing standards, such as searching, queues and lists, loops, recursion and more.

This really would have been a brilliant book if Erwig had got himself a co-author who knew how to write for the public, but sadly the style is mostly heavy…

A turnround from Tyson

I am delighted that one of our reviewers has been able to give a five star review to Neil deGrasse Tyson's latest book. The astrophysicist has taken over Carl Sagan's old post as the number one science populariser in the US, but his written output in the past has been patchy, to say the least.

There have been at least two significant problems. One is dubious history of science. For example, in the cases of both Galileo and Bruno he has passed on undiluted the comic book version of history where Galileo is persecuted for mentioned heliocentricity (rather than his disastrous political handling of the  pope) and mutters 'Eppur si muove!' at his trial, and Bruno is burned at the stake for his advanced scientific ideas (both misrepresentations). Some argue that it getting history of science accurate doesn't matter if we get the right message about science across - but if we are prepared to distort historical data, why should anyone take scientific data seriously?

The o…