DNA testing needs caution

Twelve million people in the world have reportedly had their DNA tested in order to learn something about their past and their future. That is not a large number, considering the fact that 7.7 billion people inhabit this planet. Not so long ago DNA testing was bank-breakingly expensive, which meant that very few of us could have afforded the luxury of knowing where our ancestors came from. But now the price is down to about $600, cheaper than many of the increasingly routine diagnostic tests our doctors order. It is certain that millions more people will follow suit, but there are pros and cons.

DNA testing is now popular for two main reasons: firstly, because one wants to know something of one’s ancestry; and secondly, the compulsion to ascertain whether one carries some undesirable gene that predisposes an individual to a fatal illness must be great if the disease is common in a family. These are powerful instigators.

In the 1990s, I met a young scientist from Nigeria working at Oxford University who had sequenced a gene as part of the human genome project to sequence every one of the 20,000 genes we each have. She told of the extraordinary experience and sense of accomplishment to unravel the secret of just one human gene, all coiled and fascinating six feet of it. Each gene predetermines our strengths and weaknesses, how we look, what we like, even how we think. Tiny variants produce significant differences between us. Nothing else therefore explains us to ourselves better, “Not even hundreds of hours on a therapist’s couch,” I heard someone comment. It is not surprising then that people are eager to get tested.

Many DNA testing companies have sprung up and now scientists are encouraging us to be cautious and calling for better control of the organisations that conduct the tests. The BBC recently reported that there are as many as 40 per cent of false positive results which can lead people to make unnecessary medical interventions to avert life threatening diseases that are not actually part of their story. That is an unacceptably high error ratio and the testing companies do not warn customers that error may occur. I did a test with one of the bigger commercial companies to know if I was predisposed to any serious illnesses but was not warned of the limits of the test. I was happy with my good results, not least because research shows that we can auto suggest illnesses if we think we are predisposed to have them.

I also did a DNA test to find out my ethnic make up. I was influenced by a friend’s result that tied her back to a part of the world where she had chosen to spend time for no good reason, and had felt a deep and inexplicable affinity with. The sense of geographical attachment being carried through centuries in one’s DNA gave me a new insight into the notion of “home”. I took part in the wonderful National Geographic Society’s Genographic anthropological project to map the migration of the human species as we travelled, unabated, and put down roots across the world, mutating as necessary as we adapted to new environments that were still themselves in the making.

The revelations of DNA research are useful not least for giving modern human beings a perspective on our shared history, which is pertinent, given the troubling current mass migration from Africa across the Mediterranean and the pushback from so many countries and their peoples. We all know, or should know, that we come from one source and that human beings have been moving out of Africa into Europe and Asia in waves for the last 45,000 years. Last year, Nature magazine published important new research that used a sample ten times larger than any previous one. It revealed that for most of its history Europeans were dark-skinned, descended from a singe founder population which forms part of the ancestry of present-day Europeans. About 13,000 years ago the first pale-skinned Europeans appeared and numbers grew with the arrival of farmers from the Middle East about 8,000 years ago.

The National Geographic Society is a non-profit organisation doing a worldwide anthropological project, but it is a brave new world and on the negative side of the commercial DNA trend is the customer’s lack of knowledge about how our DNA will be used, and by whom for what end. As the BBC report pointed out, we give away our valuable DNA when we send away our saliva for testing but there are no long-term safeguards, and many ethical issues are beginning to arise as security authorities in many countries are increasingly trying to access DNA genetic banks.

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