Figure 1.

Validation of light-induced rhythmicity by assessing expression of the clock output genes, per2a and aanat2, under different light conditions. (a) Schematic outlining the light conditions and subsequent experimental manipulations. (b) Expression analysis of per2a and aanat2 at 52 hpf and 64 hpf, as detected by whole mount in situ hybridization (WMISH) for larvae raised under the different light conditions, as shown in (a). ZT, zeitgeber time where ZT0 represents start of the light phase; bars above WMISH images denote the light setting at the time of fixation, white bar = light, black bar = dark; numbers represent number of larvae with displayed phenotype; hpf, hours post-fertilization; arrowheads indicate the time of expression analysis; scale bar, 100 μm; arrows mark per2a or aanat2 expression in the pineal gland.