DOI: 10.5061/dryad.t4b8gtj5w
title: Parametric effects of light acting via multiple photoreceptors contribute to circadian entrainment in Drosophila melanogaster

description: Circadian rhythms in physiology and behavior have near 24-hour
 periodicities that must adjust to the exact 24-hour geophysical cycles on
 earth to ensure adaptive daily timing. Such adjustment is called
 entrainment. One major mode of entrainment is via the continuous
 modulation of circadian period by the prolonged presence of light.
 Although Drosophila melanogaster is a prominent insect model of
 chronobiology, there is little evidence for such continuous effects of
 light in the species. In this study, we demonstrate that prolonged light
 exposure at specific times of the day shapes the daily timing of activity
 in flies. We also establish that continuous blue- and UV-blocked light
 lengthens the circadian period of Drosophila and provide evidence that
 this is produced by the combined action of multiple photoreceptors which,
 includes the cell autonomous photoreceptor cryptochrome. Finally, we
 introduce ramped light cycles as an entrainment paradigm that produces
 light entrainment that lacks the large light-driven startle responses
 typically displayed by flies and requires multiple days for entrainment to
 shifted cycles. These features are reminiscent of entrainment in mammalian
 models systems and make possible new experimental approaches to
 understanding the mechanisms underlying entrainment in the fly.
description: All data were collected using Drosophila Activity Monitors (as
 described in the methods section of our manuscript). Processed data are
 uploaded as a compressed file.
description: All files are MS Excel sheets and can be opened with any
 spreadsheet program. There is one file for each figure of the manuscript
 which contains all the data used to make the plots and perform downstream
 analyses.
description: # LightEntrainmentDataset.zip The zipped folder contains 4 MS Excel
 sheets. ## Description of the data and file structure **Figure1.xlsx**
 contains the activity data plotted in Fig. 1 and Suppl. Fig. 3. There are
 four sets of columns in the sheet called "Profiles" - one each
 for Canton-S, w1118, yw and loss-of-function cryptochrome mutants. These
 are three wildtype/background strains and one mutant for the gene
 cryptochrome. For each genotype, the Zeitgeber Time (ZT), Mean activity
 counts and across fly SEM are provided for four environmental conditions,
 i.e., (i) standard Light/Dark cycles (LD), (ii) symmetric skeleton
 photoperiods (SPP), and two asymmetric skeleton photoperiods, aSPP1 (iii)
 and aSPP2 (iv). In the sheet called "Peaks", individual
 fly's phase of peaks in ZT units are provided for two independent
 replicate runs. Data for the aforementioned four genotypes under all the
 four conditions are given. The run number is noted in the left most
 column. Entries that say NA either did not have a detectable peak, did not
 entrain or had died during the course of the experiment. **Figure2.xlsx**
 contains information of light spectrum for the various light conditions
 used and their intensities across the wavelength range. Data were exracted
 from multiple sources. See the associated preprint/manuscript for more
 information. The sheet called "Compiled" has two sets of
 columns, i.e., "RAW VALUES" and "NORMALISED TO
 MAXIMA". The "RAW VALUES" columns have the wavelength and
 intensity at that wavelength for each light condition described in Suppl.
 Fig. 1A. In addition to light spectrum information, data for the
 cryptochrome action spectrum are also provided in the two right-most
 columns. The intensity values normalized to maxima are provided in the
 "NORMALISED TO MAXIMA" set. **Figure3.xlsx** contains two
 sheets, i.e., "Dose Response" and "Comparisons across
 genotypes". The "Dose Response" sheet contains data for the
 three gentoypes, Canton-S, w1118 and yw. Data is arranged as follows: for
 each genotype, the first column has light intensity values and the second
 column has the free-running period of the fly under that intensity. The
 "Comparison across genotypes" sheet has the fly-wise
 free-running period and periodogram power values for the following
 genotypes: Canton-S, w1118, yw, cryOUT, gl[60j] and norpA. See associated
 manuscript for more details on the genotypes. The first two columns report
 the year the independent experiment was run and the fly identity. Data for
 each independent run are highlighted using different colours. Data
 provided here are depicted in Fig. 2 of the corresponding manuscript.
 **Figure4.xlsx** contains three sheets, i.e., "Entrainment
 categories", "Profiles", and "Peaks". The
 "Entrainment categories" sheet contains the data showing the
 number of entrained, relatively coordinated, free-running or arrhythmic
 flies pooled across replicates for the six genotypes mentioned above. The
 % of flies showing each of these categories is shown right next to the raw
 values and are labelled as such in the sheet. Underneath this table, a
 table documents the number and percentage of rhythmic, arrhythmic and dead
 flies for two loss-of-function clock mutants. All these are flies that
 were examined under UV- and Blue-blocked ramped light cycles with a 24-h
 periodicity. The "Profiles" sheet contains two sets of columns.
 One contains the activity counts averaged over flies under Ramps and day 1
 of constant light conditions post entrainment for the following genotypes:
 Canton-S, w1118, yw and one loss-of-function clock mutant (per01). The
 second set contains the SEM values for each of these genotypes under each
 of these light conditions. The left most column contains the time
 information as Zeitgeber Time (ZT). The sheet "Peaks" contains
 individual fly's phase of peaks in ZT units pooled across two
 independent replicate runs. Data for the aforementioned four genotypes
 under both conditions are given. All these data are described in Fig. 3 of
 the associated manuscript. ## Code/Software All these files are executable
 in MS Excel or any spreadsheet program.