Genetic testing is all the rage, but its promise is limited

New technologies often take decades to reach Indian shores. Not so in the case of genetic testing. Within 10 years of the launch of the world’s first direct-to-consumer service, genetic testing has found a booming market in India.

Your DNA, unless you have an identical twin, is unique. The idea behind any genetic test is to understand whether the sequence of bases in your DNA have something useful to tell you. Those on offer in India can cost anywhere from ₹1,000 to ₹50,000.

Who’s your daddy?

One of the most popular genetic tests in India is used to test paternity. Be it a doubting husband or a long-lost son, these “peace-of-mind tests” can set the record straight. Their effectiveness is so high that Indian courts have used paternity tests as definitive evidence. Take the example of Congress politician ND Tiwari. In 2008, 28-year-old Rohit Shekhar claimed that Tiwari was his biological father. After a long-drawn battle, the court ordered a paternity test in 2012 and closed the case in favour of Shekhar.

This is how paternity testing works. A child inherits half their DNA from each parent. For the test, DNA samples in the form of cheek swabs are taken from all three individuals. These samples are then treated with restriction enzymes, which cut each DNA at pre-determined places. These cut-up pieces are then suspended in a solution and run through a gel, which lets shorter pieces run faster than bigger pieces. The pieces show up as dark spots on a light background. If the parents are indeed those making the claim, the child’s DNA patterns will appear to be a combination of the patterns of the parents.

This technique, called DNA fingerprinting, was developed in 1984 and has also been used to produce forensic evidence in thousands of criminal cases. Instead of comparing a DNA sample of a child with two others, say, it could be used to compare DNA found in some hair at a crime scene with that of the accused perpetrator.

Not the oracle

Not all genetic tests are so effective at giving useful information though. Many companies market genetic test results as a fortune-telling scroll. They claim that, based on your genetic information, they can predict whether you will get a disease or not. This is far from the truth. At best, genetic testing for health outcomes can be seen as a weather map, where predictions can be true but quite often they aren’t.

Even if genetic testing companies make this clear in their fine print, they haven’t done enough to correct public perception. For instance, a 2010 European survey revealed that nearly half of those asked felt “all children will (soon) be tested at a young age to find out what disease they get at a later age”.

While certain diseases, such as Huntington’s disease, have specific genetic mutations to blame, most diseases are a combination of environment, lifestyle and genes. There is no “gene for breast cancer”. Genes are indeed powerful, and they influence our appearance, intelligence, behaviour and health. But unlike what the public believes, genes do not determine those outcomes.

These public beliefs matter because they can and will affect policy. After 13 years of debate, in 2008 the US passed the Genetic Information Non-discrimination Act to ensure that insurance providers do not discriminate customers based on their genes. Before the genetic testing market in India explodes to ₹800 crores by 2018, as some predict, we need a similar act to safeguard people’s privacy. And even after that, treat any genetic test results with skepticism and care.

First published in Lokmat Times.

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2 thoughts on “Genetic testing is all the rage, but its promise is limited”

  1. Hey Akshat. There is so much more to genetic testing than you’ve described here for the public market, obviously within the health market but also within personal health development too. There are a growing number of sports companies who are profiling athletes and helping them to work out how they can push or layback on certain training to maximise their growth as an athlete. In parallel nutritional is being tweaked by understanding more about different phenotypic profiles.
    I know this all sounds a bit faddish, but when you get past the commercialism of the market, there is great potential for this emerging market of mega population data to come into its own so we can learn even more about our mosaic of human genomics.

    1. You’re right. The field of genomics is fascinating and its applications to human enhancement may just be taking off. I didn’t mention those because of the word limit of writing for a print publication. My aim was to warn people to not expect such tests to give definite health predictions. When it comes to being open about learning and perhaps tweaking your environment/lifestyle, genetic testing could indeed be useful.

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