Sleeping is all in the genes

Scientists have found the reason why some people need more sleep than others lies in their genes. A survey of more than 10,000 people showed those carrying the gene ABCC9, present in one in five of us, slept longer than the average of eight hours. The finding, which is published in Molecular Psychiatry, could explain why Margaret Thatcher only needed four hours a night as Prime Minister while Albert Einstein was said to sleep for 11.