This article was taken from the March 2016 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
Angelina Jolie Pitt has probably done more to raise the public profile of genetics than any other person. Her announcement that she carries an abnormal version of the BRCA1 gene responsible for the cancer that killed her mother, followed by surgery to remove her breasts and ovaries, was a bold statement of belief in the power of genetic testing to predict disease.
Jolie Pitt's analysis, we can assume, was delivered by her doctor alongside appropriate genetic counselling in a healthcare setting. But this isn't the only way to take a look inside your genes. For £125 you can fill a tube with saliva, pop it in the post to 23andMe and receive a genetic treasure trove.
But while a growing number of people are getting their genomes done the DIY way, there are some big issues to be aware of. I'm not talking about the challenges of privacy and data ownership -- although those are more than a little terrifying. I mean the fundamental underlying biology.
Decades of media coverage about how our genes work has driven home the concept that genes are "for" something, be it baby-blue eyes, breast cancer or a propensity to a punch-up. But examples like BRCA1 -- whereby a single genetic mistake hugely increases the risk of a particular disease -- are rare. And even carrying the fault isn't a cast-iron guarantee: there's a 60 to 90 per cent chance of breast cancer, and around 50/50 odds on ovarian cancer.
Our genes don't act in isolation. Every letter of our DNA is a tiny part of our bigger human story. In any two human genomes there are millions of differences, and their effects are interdependent. Sometimes the effect of a particular gene fault might be cancelled out or enhanced by other variations in the genome. Or it might be influenced by random wobbles in our biochemistry, or influences from the environment. Sorting the genetic wheat from the chaff is a tough task, and one that researchers are only just embarking on in any serious way.
We're all have a smattering of potentially dangerous or even deadly gene faults, as well as millions of random and inconsequential differences peppered throughout our genome. But you might never even know about it until you start ferreting around in your DNA. And once that Pandora's box is open, what are you going to do about it?
I've never had my genome analysed, but I know people who have. Although they found their results interesting, there was little significant information that they couldn't have figured out from their family history. And the health advice to reduce the risks of diseases as diverse as Alzheimer's and cancer comes down to the usual boring stuff about not smoking, taking plenty of exercise and watching one's weight.
DIY gene testing may be a useful starting point to get people engaging with their genomes -- an increasingly urgent need as medicine becomes ever more tailored to our individual genetic quirks. But its runes should be read cautiously, at least until we understand a lot more about how the genome works.
To put it simply: everyone's a little bit mutant. We just don't know how much it matters.
Kat Arney is a UK-based science writer and broadcaster. She is the author of Herding Hemingway's Cats: Understanding How Our Genes Work (Bloomsbury)
This article was originally published by WIRED UK
