Coming to a friend near you: DNA sequencing

Sue Malcolm, Faculty Member in Genomics & Genetics, examines the issues behind the UK government's plans to sequence a patient's entire genome.

Guest post by Sue Malcolm. Sue’s original post was published on her blog, Me & My Genes, on Jan 25th.


If the UK government’s ambitious plans to introduce sequencing of 100,000 patients’ whole genomes come to fruition, then it’s likely to affect you, or someone you know, pretty soon. So it may be about time to brush up your genetic code, get intimate with your methylation and generally marvel at how much the study of DNA and genetics is telling us about the world around us.

Human Genome

Over the last few years, the ability of machines to read the sequence of the entire DNA content (genome) of an individual (or a banana) has become vastly quicker to do and vastly cheaper. Because this has advanced so quickly since the Human Genome Project just a few years ago, it’s usually called next generation sequencing. The entire sequence actually tends to give us too much information, or certainly more than we understand properly, so it’s more usual to sequence just the bits we believe provide the code for the proteins in a cell, generally called whole exome sequencing and which only make up a few per cent of the total.

Prime minister David Cameron announced that, from April 2014, 100,000 patients with cancer or rare diseases will have their entire DNA sequenced, funded through the NHS. He said, “By unlocking the power of DNA data, the NHS will lead the race for better tests, better drugs and above all better care”. An ambitious and exciting target. Other nations are gearing up to do similar but much less ambitious work, and the British effort is unusual in that sequencing of the whole genome is proposed. This may be modified in the set-up period and certainly the cost will have to come down even more significantly before it can get going.

Of course, genetics is not an ethics free zone – quite the opposite. There is much debate between professionals about what they are doing and why, but a significant problem is that sometimes the findings are so extraordinary and unexpected that ethical discussions may not always have taken everything into account. This video explains DNA sequencing and disease risk in more detail.

As far as we know, there have been no decisions made by the UK government or the NHS about how much information will be fed back to the patient. Will they pass on any information about changes potentially causing serious diseases, and perhaps more significantly, will patients want to know?


Sue Malcolm

Sue Malcolm is Emeritus Professor of Molecular Genetics at the Institute for Child Health, University College London. She won the 2011 ‘Genomics & Genetics Faculty Member of the Year’ award in 2011, and has been a Faculty Member since 2001.

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