Can genetics explain why some people thrive on less sleep?

For as long as Brad Johnson can remember, he has never been able to sleep more than six hours a night. Most nights, he sleeps even less. Johnson, 63, always wakes without an alarm clock, feeling rested and ready for the day.“If you paid me $100,000 to sleep eight hours tonight, I couldn’t do it,” he said.He’s not the only one in his family like this. Two of his seven siblings also are natural short sleepers. He suspects that their father was one, too.At least 15 years ago