Project description: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 confirmed these observations using whole genome bisulfite sequencing (WGBS). In line with previous studies we observe that DNA methylation is elevated in the first exons downstream of the transcription start sites (TSS). Moreover, 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, and motivate further exploration of epigenetic regulation in this organism and its response to environmental factors.
Project description:Juvenile hormone (JH) and JH agonists have been reported to induce male offspring production in various daphnids including Daphnia magna. We have recently established a short-term in vivo screening method to detect chemicals having JH activity, induction of male offspring, using adult D. magna. Diofenolan has been developed to be a JH agonist in insects, but no male induction in daphniids has been studied. In this study, we found the male offspring induction by diofenolan with a short-term in vivo screening method, and the most potent male offspring production activity among JH analogs studied using the OECD TG211 Annex 7. Transcriptome analysis of diofenolan-exposed D. magna showed up-regulation of JH-responsive genes. These results clearly demonstrated that diofenolan has JH activities in D. magna using the short-term in vivo screening assay, OECD TG211 Annex 7 and microarray analysis.