A landmark study is to sequence the entire genome of 3000 people in an attempt to uncover the genetic roots of Type 2 diabetes, the Times newspaper has reported. The investigation, costing £15 million, is being carried out by an Anglo-American team. It is hoped that the results will help find improved ways to diagnose and treat the condition.
Diabetes affects two million people in the UK and can cause heart disease and strokes, yet its underlying causes are poorly understood. Lifestyle factors such as poor diet and lack of exercise have been known for some time to play a role, but scientists have become increasingly aware of the part played by genetics.
Current research into the causes of the condition relies on comparing snapshots of the DNA of people with Type 2 diabetes with that of healthy control subjects. While this method has revealed about three dozen DNA variations that affect the disease, they only account for a small part of the heritable factors known to play a role. The missing heritability is thought to be caused by variations that are too rare to be found by current techniques.
This study marks the start of a new phase of research where entire genomes are being screened. The scientists will sequence the entire DNA of 1500 people with Type 2 diabetes and 1500 people without the condition. They will then compare the results and look for variations that are more common in the group with Type 2 Diabetes. The study will also investigate how DNA influences other conditions such as heart disease and cancer.
Until only recently this type of study was prohibitively expensive. In the past, sequencing the thousands of genomes required would have cost $1 billion. Now, thanks to new techniques for reading DNA, the price for each genome is £5000. The work should be completed by the middle of 2011.
Mark McCarthy, Professor of Diabetes at the University of Oxford, who is leading the British side of the study said: 'We are moving genomic research into a new phase... We will be able to pin down many more genetic effects on disease, to understand the biology more completely and give the pharmaceutical industry new targets for drugs'.