Mutants have a lengthened rest phase (π). Phase response curves (PRCs) change from a low amplitude, Type 1 to a high amplitude, Type 0 with increased duration of the light pulse. The lengthening of circadian period is a consequence of changes in the time course of the oscillation in the late subjective day.

Long cycle duration, the evening peak of activity is shifted to a later time than wild type.

A long period biological rhythm mutant that does not have learning deficits.

Measures of acquisition at intermediate and maximum levels and of 30 min memory retention are normal. Mean Courtship Index (CI) for males exposed to fertilised females for 30 mins does not differ significantly when exposed to other fertilised females. After 30 mins exposure of an immature male to another immature male a significantly suppressed response to another immature male is observed.

The activity rhythm period of per^L2/Y flies is lengthened by CkIIβ^And, by 3.0 hours.

The circadian locomotor activity rhythms of adults exhibit 28-30 hour periodicities at 25^oC. At lower temperatures in constant darkness adults exhibited shortened periodicities, at higher temperatures the periodicities were lengthened. In conditions of cycling light (12h light and 12h darkness) the pacemaker can be reset to exhibit 24h rhythmicity and the 'evening peaks' of locomotor activity are in the evening.

Individuals have longer circadian rhythms than wild type. Males show defective courtship conditioning (Jackson, J. Comp. Phys. A 151: 545).

circadian rhythms; long period