Cellana rota Raw sequence reads

At the meeting point between sea and land, intertidal inhabitants are exposed to the 24 hour solar day, and the 12.4 hour rising and falling of the tides. One or both of these environmental cycles govern intertidal organisms' behaviour and physiology, yet little is known about the underlying molecular clockworks of tidal rhythmicity. Here, we show that the Red-Sea limpet Cellana rota exhibits robust tidally rhythmic behaviour and gene expression. We assembled a de-novo transcriptome, identifying more tidal than circadian rhythmic genes. We identified numerous tidally rhythmic genes and pathways associated with the circadian clock, sleep and hypoxia, among them, a known circadian clock gene, Protein phosphatase 4c. Most of the putative circadian core clock genes were identified in C. rota. The expression of a Rhodopsin homolog increased around full moon versus quarter moon nights. We show that not only is the behaviour of an intertidal organism in tune with the tides, but so too are a major proportion of its genes and pathways, many of them putatively circadian.