Meeting Abstract
There is currently great interest in the role of epigenetic factors in phenotypic plasticity and acclimatization. In a typical envisioned scenario, epigenetic modifications are adjusted in response to external cues resulting in gene expression change to fit environmental conditions. Thus far, however the evidence of this mechanism in invertebrates has been lacking. Here, we sought to quantify the change in gene body methylation (gbM, the predominant type of DNA methylation in invertebrates) relative to gene expression change in a reef-building coral upon transplantation to a novel environment. Twenty colonies of Acropora millepora were divided in half and reciprocally transplanted between reefs separated by five degrees of latitude on the Great Barrier Reef. Gene body methylation was measured using methylation-binding-domain enrichment coupled with Illumina sequencing (MBD-seq). Colony identity was the strongest predictor of gbM, despite the fact that the coral halves spent months in different environments. Despite abundant changes in gene expression (315 differentially expressed genes) we detected no differentially methylated genes in response to transplantation. In contrast, over 100 genes were differentially methylated based on corals’ origin. Similarly, correlation network analysis revealed multiple clusters of epigenetically correlated genes related to origin and growth rate, but none related to transplantation. Notably, differential methylation depending on corals’ origin was positively correlated with difference in gene expression among populations. We conclude that changes in gbM do not drive molecular acclimatization in A. millepora. Instead, differences in gbM between populations predict variation in gene expression that is unresponsive to environmental change.
