Lack of PDF and CRY signaling causes arrhythmic behavior under DD.

Group averaged actograms of each genotype under constant darkness (DD) following LD cycles. (A) w¹¹¹⁸ flies; (B) pdfr⁵³⁰⁴ single mutant flies; (C) pdfr⁵³⁰⁴; ; cry^b/01 double mutant flies; (D) cry-G4⁽¹⁹⁾; cry^b ss Pdf⁰¹double mutant flies. The double mutant flies fail to maintain free running rhythms. For the experiment shown here, the numbers of animals averaged are 16 (A), 15 (B), 29 (C), and 24 (D).