A decade or so after scientists triumphantly revealed a first draft of the human genome, the 3bn biochemical letters that make up our DNA, the script is turning out to be far harder to decipher – and therefore to use – than the enthusiasts led us to believe.
But the huge research effort to understand the complexity of the genome is throwing up new insights into the nature of humanity, as the Danish science writer Lone Frank shows in My Beautiful Genome, her excellent look into the postgenomic world. To illustrate the issues, she takes the ultra-personal route of undergoing as much genetic testing as she can. This technique worked well for Masha Gessen in Blood Matters (2008) and David Ewing Duncan in Experimental Man (2009), and it succeeds for Frank too.
The era of consumer genetics, which moved testing beyond specialist laboratories into the mass market, began three or four years ago when companies such as deCODEme and 23andMe launched personal gene profiling services.
Frank explains their limitations well. For a start, the companies only decode less than one-thousandth of the genome, focusing on the mutations in individual letters of the genetic code known as SNPs (usually pronounced “snips”, which stands for single nucleotide polymorphisms).
Consumer-oriented tests scan about a million SNPs looking for variants that scientists have shown to be linked to disease, usually through research projects that compare the genomes of patients with a control group of non-sufferers. As Frank discovers when she undergoes a SNP scan from deCODEme – and as I have found myself – the results are generally reassuring. For the most dreaded genes, those that predispose to Alzheimer’s, her results are “outright fantastic”.
But Frank is not satisfied with mere SNPs. She wants to have her full genome read but this is still at the research stage and would cost thousands of dollars, compared with a few hundred for a SNP scan – if she could find a lab to do it. And many experts believe that existing knowledge of the links between genes and disease lies mainly in SNPs, with little extra insight to be gained from the rest of the genome.
So she moves on to more specialised tests for conditions that she knows run in her family, such as mental illness and breast cancer. However, Frank fails to pick up any conclusive information – demonstrating the limitations of genetics rather than her failure as an investigative writer. In the process she has fascinating discussions with several of the world’s leading geneticists and offers sharp and colourful observations.
Frank can also be devastating about herself, as when she undergoes personality tests and is told: “Your agreeableness couldn’t be lower … Then there is your low score on altruism and sympathy.” I do not know whether Frank is really disagreeable and unsympathetic but, given the underlying warmth of her writing, I doubt it.
The conclusion summarises beautifully the latest evidence about the malleability of our DNA in response to social and environmental circumstances. “My genome is not a straitjacket but a soft sweater to fill and shape, to snuggle up and stretch out in,” Frank writes. “So who am I? I am what I do with this beautiful information that has flowed through millions of years through billions of organisms and has, now, finally been entrusted to me.”
Clive Cookson is the FT’s science editor
My Beautiful Genome: Exposing Our Genetic Future, One Quirk at a Time, by Lone Frank, Oneworld, RRP£10.99, 312 pages