A remarkable study published in Science this week identifies a rare mutation in the gene DEC2 which influences the duration of sleep in humans. The authors started with a family where patterns of short sleep (about 6 hours of sleep a night on non-workdays, versus ~8 hours for other people in the family) seemed to follow a Mendelian inheritance pattern. In a candidate gene resequencing study, they identified a mutation in all of two people--a mother and daughter--with the short sleep pattern.

In what can only be described as a ballsy move, the authors then invested what must have been a considerable amount of time and money on following up this mutation. Which, I emphasize again, was found in only two individuals in a single family. In particular, they generated mice carrying both of the human versions of the gene, and were thus able to explicitly compare the two human alleles in an animal model. (This is in contrast to most mouse studies, which completely remove a gene or dramatically up-regulate it). Not wishing to show any mammalian bias, they did the same thing in flies. In all cases, the results were consistent with the human data--the low-sleep allele led to increased activity in both species.

Out of curiosity, is 6 hours of sleep (without an alarm clock) really all that odd for people? It certainly would be for me, but I feel like I know plenty of people who claim to naturally need only about that much.

Labels: Genetics