Abstract
Mutations at the
period (per) locus of Drosophila melanogaster disrupt several biological rhythms. Molecular cloning of DNA sequences encompassing the
per
+ locus has allowed germ-line transformation experiments to be carried out. Certain subsegments of the
per region, transduced into the genome of arrhythmic
per
o flies, restore rhythmicity in circadian locomotor behavior and the male's courtship song.