Now I know what my problem is :-)

A typical day that begins for me at 530 or so ends by 1130 or midnight. Which means I usually sleep for just under six hours. Given how much science has not fully understood sleep, and given that most people sleep for eight hours (or even more on weekends in particular) I have wondered if my sleep habit was ok. Hey, science rescues me with this report that early risers are mutants:

now they say they have found the first genetic mutation in humans that appears to affect sleep duration rather than sleep timing. The mutation lies in DEC2, a gene that codes for a protein that helps turn off expression of other genes, including some that control circadian rhythm, the internal clock that regulates a person's sleep-wake cycle. The mutation occurred in just two people, a mother and her daughter. The women sleep an average of only 6.25 hours, whereas the rest of the family members sleep a more typical 8 hours.

To confirm that this mutation shortens sleep, Fu and colleagues engineered mice to carry the mutant form of DEC2. The mutant mice slept about an hour less than normal mice, the team reports today in Science. The finding also held for fruit flies: Mutant flies slept about 2 hours less than normal flies.

DEC2 likely isn't the whole story when it comes to short sleep. "Genetic control of sleep is going to be complex and is going to include multiple types of genes," says Shaw, who was not affiliated with the study. But that doesn't diminish the importance of this paper, he notes. "It's really an amazing piece of work."

Am glad to join the X-Men :-) HT