Why lie-ins may run in the family

Experts believe our genetic make-up determines exactly whether we are early or late risers - dubbed larks and owls.Neurogeneticist Dr Louis Ptacek, of University of California, says understanding a person’s chronotype - the time of day they function best - can help us live more healthily.Dr Ptacek told the BBC: ‘Whether we like it or not, our parents are telling us when to go to bed - based on the genes that they gave us.’We all have internal circadian clocks - our master clock is made up of thousands of nerve cells in a wing-shaped structure located in the hypothalamus, at the base of the brain.The hypothalamus controls all kinds of bodily functions, from releasing hormones to regulating our temperature and water intake. This internal clock is reset every day by light.You might expect that since the earth’s day lasts 24 hours, everyone’s clocks would run to a similar schedule. But they don’t. That’s why there are larks and owls.Families of extreme owls, with Familial Delayed Sleep Phase syndrome, were found to have a different mutation in the same genes.Rick Neubig, a professor of pharmacology in Michigan, said he is an extreme lark.‘People I communicated with in Europe will always notice that they get emails from me very early in the morning. The other thing I like a lot which fits in with the early mornings is that I’m a fairly serious bird watcher.‘It’s much easier for me than other people to get up and see the birds at dawn.’He said his early starts run in the family.‘My mother would always drag us out of bed at 4 in the morning to go on vacation, and my daughter works out early in the morning.’Dr Louis Ptacek, who is studying families like Rick’s that have Familial Advanced Sleep Phase syndrome, said he started researching sleep patterns after his colleague Dr Chris Jones met a 69-year-old who was worried about waking up very early.Dr Ptacek said: ‘We recognised this was a strong genetic trait. We found the mutated gene resided near the end of chromosome 2.’Prof Derk-Jan Dijk, Head of the University of Surrey’s Sleep Research Centre, said: ‘If you have a fast clock you like to do things early, and if you have a slow clock you like to do things late.’(dailymail.co.uk)ANN.Az