Genomics is awesome, but terrifying too

Increasingly, scientists will have what was once seen as godlike power. But how can we trust them with it?

The first thing to say about Chief Medical Officer Dame Sally Davies’s call yesterday to introduce genomic medicine widely into the NHS is that she is right to be excited. Around the world right now, our growing capacity to identify and even tweak our own genes – whose activity, inactivity, or mutation lies behind many diseases – is the great new frontier of medical science. People such as Lord Ara Darzi, perhaps Britain’s most distinguished doctor, view the ability to intervene on a cellular level, Fantastic Voyage-style, with awe.

For them it is a natural step in the evolution of medical understanding. Until only decades ago, doctors had to cut patients open to get at the bits going wrong. Since then, surgery has grown steadily less invasive and traumatic. Mapping or manipulating the genes of individual patients to offer personal treatment at microscopic scale is the obvious culmination of that trend.

The second point is that, though it may seem like science fiction, genomics already offers practical solutions. Take, for example, the pilot programme that Davies hopes to roll out, known as the 100,000 genomes project. It identified the cause of 13-month-old Jessica’s mysterious, violent seizures by comparing her genetic code with a standard human genetic sequence. Some 6.5 million genetic variations were uncovered, of which just under 700,000 were as rare as her condition, and just 3,000 had a critical impact. Between them, her parents possessed all 3,000 – bar 67. Because they didn’t have the disease, the root cause lay with one of those 67 mutations. When these were crossreferenced against a database of symptoms, just one matched: Gene SLC2A1, which creates a protein that transports sugars to the brain.

It turned out that the baby girl only had one copy, where she should have had two. As a result her brain was not getting enough fuel to operate properly. By identifying Jessica’s incredibly rare, otherwise hopeless disease, genetic screening had also identified a simple course of treatment: changing her diet to compensate for the sugar deficiency.

Such cases prompt normally mild-mannered doctors to use such words as “revolutionary”. And this is the third point to make about Davies’s remarks: the revolution is, above all, happening here, in the UK.

This is something to be hugely proud of, and encourage further. For the potential of genomics is immense, and whether you like it or not, will change not just how we are treated as patients, but who we are as people. New gene editing technology has the power not only to modify the genetic code of individuals, but of all their offspring too. In this way genes responsible for hereditary disease, say, could effectively be edited out of humanity’s genetic recipe forever.

But at what cost? Geneticists talk excitedly about the real possibilities of gene therapies “curing cancer in the young within decades” or even curing HIV right now. But those scientists also talk about the fact that there are still glaring gaps in their understanding. For example, they know that one gene is a big indicator of breast cancer. But what else does it do? Why has it not been evolved out of circulation if it only has negative effects? Maybe it does something positive, critical even, that we have no knowledge of? What then are the risks of permanently removing it from humanity’s gene pool?

It’s not just us. Every organism on the planet has a genetic code, so genetic manipulation has almost limitless possibilities – from the prosaic to the bizarre – in species both living and dead. Scientists have already spliced the DNA of woolly mammoths into that of elephants, and the “de-extinction” of lost species is now a logical probability. Last November a study was published in which blind rats had their sight restored by the editing of faulty genes. “It’s like the Bible,” a scientist told me earlier this year.

And that is the final point to make. Genetic advances will inevitably encourage scientists to turn Creator. That should give us all pause. So, for all their potential omnipotence, geneticists must convince the rest of us that we can trust them, whether it be with our data, or with the future of our species. Despite the complexity of their lab work, this will be their hardest task. They must now apply themselves to it with fearsome dedication, or risk all the undoubted benefits of genomics slipping from their grasp.