Liu, R.; Morselli, M.; Yampolsky, L. Y.; Peshkin, L.; Pellegrini, M.

Daphnia magna is a widely used model organism in ecological and evolutionary studies. DNA methylation in D. magna can influence development and adaptation to changing environments. Previous studies have demonstrated that D. magna is generally hypomethylated. In this study we characterized the DNA methyltransferases and profiled DNA methylation using whole genome bisulfite sequencing. We find that D. magna contains lowly expressed functional methyltransferases and a highly expressed nonfunctional de novo methyltransferase. In line with previous studies, we observe that DNA methylation is found at low levels at CpG dinucleotides, depleted over promoters and elevated in the first exons downstream of the transcription start sites, and that these exons are hypermethylated compared to adjacent introns. In contrast to prior studies in Daphnia, we found no significant changes in DNA methylation with age. These observations extend our understanding of the epigenetic landscape in D. magna.