By Valerie Perini

Like other animals, reef building corals experience shifts in their environment throughout the day, and can respond to these diel (diurnal vertical migration) patterns with changes in behavior, growth and even gene expression. Some corals, including the Caribbean Acroporas also have a strong division of labor within colonies, and differences in gene expression are also associated with different regions of the colony specialized to perform certain tasks. A new study by recent MSC PhD recipient Elizabeth Hemond and Associate Professor Steve Vollmer investigates the interaction of these diel patterns with colony division of labor by measuring gene expression in the branching staghorn coral, Acropora cervicornis.

In the study, recently published in the journal, Molecular Ecology, Hemond and Vollmer used RNA sequencing technology to evaluate changes in gene expression between branch tips and bases, at different times of day. Results indicate that 6% of genes were differentially expressed between branch tips and bases, 1% were differentially expressed between day and night, and some gene expression patterns were impacted by both time and location within the colony. In particular, genes coding for photoreceptors, circadian rhythms, stress response, and metabolic processes varied between day and night.

The findings of this study indicate that genetic responses of corals to day versus night varies within a single colony. This work contributes to a growing body of knowledge regarding the way that coral gene expression is impacted by environmental fluctuations.