Evolution: Fruit Fly Clocks on the Edge Charalambos P. Kyriacou  Current Biology  Volume 27, Issue 6, Pages R227-R230 (March 2017) DOI: 10.1016/j.cub.2017.02.017 Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 1 Less robust, less photosensitive circadian clocks in northern Drosophilids. The geographical origins of the populations of D. melanogaster and D. virilis group species used by Menegazzi et al. is shown with a figure of the locomotor profiles of D. melanogaster and D. ezoana under LD20:4 (from [12]). ‘Zeitgeber time’ refers to the light entrainment regime with lights on at 0 h and lights off at 20 h and is shown as a horizontal bar above the locomotor activity (open, day; black, night; gray, twilight). Note that the evening component of D. melanogaster activity peaks several hours before lights off whereas the evening peak of D. ezoana activity tracks the dusk twilight signal before lights off. The underlying cause for this difference in phenotypes is the reduction of PDF and CRY expression in specific clock neuronal groups in D. ezoana that gives rise to a clock that is less robust and photosensitive. Current Biology 2017 27, R227-R230DOI: (10.1016/j.cub.2017.02.017) Copyright © 2017 Elsevier Ltd Terms and Conditions