17 June 1994
Vol 264, Issue 5166

About The Cover

The Clock mutant mouse has an abnormally long circadian period, which causes rhythmic behaviors—such as locomotor activity—to cycle every 27 to 28 hours instead of the usual 24. The generation of this behavioral mutation in Clock and other advances in the behavioral genetics of humans and animals are discussed in this special issue on Genes & Behavior. See the special section beginning on page 1685. [Photo: Dewey Hentges, Chicago, IL]