Background: Most animals restrict their activity to a specific part of the day, being diurnal, nocturnal or crepuscular. The genetic basis underlying diurnal preference is largely unknown. Under laboratory conditions, Drosophila melanogaster is crepuscular, showing a bi-modal activity profile. However, a survey of strains derived from wild populations indicated that high variability among individuals exists, including flies that are nocturnal. Results: Using a highly diverse population, we performed an artificial selection experiment, selecting flies with extreme diurnal or nocturnal preference. After 10 generations, we obtained highly diurnal and nocturnal strains. We used whole-genome expression analysis to identify differentially expressed genes in diurnal, nocturnal and crepuscular (control) flies. Other than one circadian clock gene (pdp1), most differentially expressed genes were associated with either clock output (pdf, to) or input (Rh3, Rh2, msn). This finding was congruent with behavioural experiments indicating that both light masking and the circadian pacemaker are involved in driving nocturnality. Conclusions: Our study demonstrates that genetic variation segregating in wild populations contributes to substantial variation in diurnal preference. We identified candidate genes associated with diurnality/nocturnality, while data emerging from our expression analysis and behavioural experiments suggest that both clock and clock-independent pathways are involved in shaping diurnal preference. The diurnal and nocturnal selection strains provide us with a unique opportunity to understand the genetic architecture of diurnal preference.
Bibliographical noteFunding Information:
Financial support has been provided by the Biotechnology and Biological Sciences Research Council (BBSRC, UK) grant BB/G02085X/1, which funded the postdoctoral fellowship of the lead author and supplies to conduct this research project. The Israel Science Foundation grant (1737/17) to Eran Tauber also funded research supplies. We confirm that each funding organization granted the funds based on research proposals, allowing all the experimental work and had no influence on the experimental design, data analysis or interpretation, and manuscript writing.
© 2020 The Author(s).
- Circadian clock
- Diurnal preference
ASJC Scopus subject areas