Personal genomics: how the future might cheat us of our present

Personal genomics: how the future might cheat us of our present

No. This isn't (another) personal genomics blog on how trying to find out what might kill you tomorrow can unpredictably impact you today.

The 'present' I want to talk about is the gift of improved DNA sequencing to today's medicine, and how it is being eclipsed by the flashy, crystal-ball allure of tomorrow's whole genome.

To keep us focussed on the right ball in the right game, we have found it helpful to separate personal genomics into two arms: medical genomics (DNA tests in patients) and predictive genomics (DNA tests in the healthy).

Medical genomics is a well established, generally uncontroversial, type of medicine that has existed for many years. The aim of DNA testing in someone who is unwell is the same as any other medical test, namely to help provide the best possible management for their illness. As individuals and societies we have fully embraced the concept of trying to do everything we can to make the ill better.

Predictive genomics, i.e. doing a DNA test in someone who is healthy to give information about future risks, is currently only performed in specific, restricted situations. The prospect of reading our futures is unfamiliar, seductive, steeped with hopes and fears in equal measure. As individuals and societies we don't know quite how to feel or deal with it. It is appropriate and inevitable that much discussion, head-scratching and soul-searching will occur as our knowledge, choices and opinions evolve.

Improved DNA sequencing is advancing both types of personal genomics. In particular it can be used to make medical genomic testing better, easier, cheaper, faster and more available to more patients. In many situations, sequencing the whole genome is not required and adds unnecessary challenges. It's like using a car to visit your next-door neighbour.

But whole genome sequencing is being peddled as a panacea, making other sequencing tests appear parochial and pointless. This is partly being driven by the promotion of unrealistic costs of whole genome sequence testing. These costs typically only cover production of the sequence, not the high costs of the essential analysis and interpretation of the 3 billion letter DNA code generated.

To take the car analogy a bit further. Consider if a new technology made Doc's Back to the Future time-travelling DeLorean a realistic prospect and could also be used to cut 10% off normal car journey times. Naturally, time-travel would be hugely exciting, with many potential benefits, but would require extensive and careful consideration on numerous fronts. Whilst doing that we would likely just implement using the technology to make normal car journeys a bit better. We wouldn't think that was a pointless enterprise because in 5-10 years one might be able to get to the same place with the time-travelling model.

DNA sequencing is similar. Using it to read our whole genome is highly likely to be a transformative technology that will affect us all. But whilst we get there it can be used in a multitude of ways to help patients.

We should give attention to making those things happen.