People who like a lie-in may now have an excuse to stay in bed longer, because scientists have found that the behavior is partly linked to peoples genes. 　　According to experts, who studied more than 10,000 people across Europe, it is found that those with the gene ABCC9 need around 30 minutes more sleep per night than those without the gene. 　　While the gene ABCC9 is involved in sensing energy levels of cells in the body, scientists say that those carrying the gene need more sleep than eight-hour average. 　　Scientists have also found that the fruit flies, who don't have gene ABCC9 sleep for three hours less than normal. However, sleep expert indicated that the gene should not take the blame for lie-in, because although it has such effect on us, it can still, in a way, be irrelevant to our sleep behaviors, unless we actually obey it.