TABLE 2.

Re-entrainment to delayed LD cycles

		Response categories %
Genotype	N	In synchrony with orig cycle	Resynchronized	Partially resynchronized
norpAP24	45	0	89	0
cry01,02, or 03	21	0	95	0
norpAP24cry01,02, or 03	115	37	15	43

Flies were entrained in 12:12 LD cycles then exposed to 8-hr delayed LD cycles. The ability of a fly to resynchronize to the new LD regime after 6 days was judged by inspecting that individual's actogram. Outcomes in the first data column here refer to flies whose locomotor components remained ostensibly in synchrony with the original (orig) LD regime (which could mean “no entrainment,” i.e., free-running behavior with ∼24-hr periodicity). The second data column documents flies whose activity was changed to conform with the postshift LD cycle, during at least 3 days after the 8-hr delay. Partially resynchronized: flies whose daily peaks of locomotion were judged to have conformed to neither the old nor the new LD regime, by 6 days after the shift. 11% of the norpA^P24 flies and 5% of each of the norpA^P24 cry⁰ and cry⁰ types became arrhythmic after phase shift (so the values in a given row do not sum to 100%). N, total number of flies rhythmic in initial LD. Doubly mutant individuals whose cry⁰ knock-out was derived from strain 01 exhibited the worst ability to resynchronize their behavior (postshift); but the cry⁰²- or cry⁰³-including flies of this type were only slightly better off.