Figure 4.—

Locomotor behavior of singly-mutant cry⁰ and norpA^P24 flies and of doubly mutant norpA^P24 cry⁰ ones after a shift from 12:12 LD to a novel cycle duration. Each animal was released from the second L:D conditions to DD. (A and B) Singly mutant norpA^P24 and cry⁰ individuals that resynchronized (resynchron.) to the new light regime, exhibiting ∼28-hr periods during 14:14 LD; signified by the upper-left to lower-right slant of the locomotor events during this photic condition (this being a typical long-period feature of an actogram component, vis-à-vis the two successive 12-hr days indicated on the abscissa). (C) A norpA^P24cry⁰ fly that failed to resynchronize to 14:14 LD, maintaining free-running periodicity (∼24 hr) in both photic conditions. (D) A doubly mutant individual for which two rhythmic free-running (F-R) components (comp.) appeared after it was shifted to 14:14 LD; one component possessed a period <24 hr; the second component was ∼26 hr. (E) A double mutant that behaved with a single free-running component of ∼26 hr. (F) Example of a locomotor result influenced by the two mutations and (environmentally) by the “lights-on” transitions; this norpA^P24cry⁰ individual displayed its highest activity during the light part of LD cycles but failed to re-entrain to 14:14 LD; a feature of the behavior plotted in this panel is “disconnected” locomotor during days 10–11 (arrow); for the remainder of the behavior occurring in 14:14 LD, this fly behaved with an ∼24-hr period.