Transgenerational DNA Methylation Changes in Daphnia magna Exposed to Chronic γ Irradiation

In collaboration with researchers from the French nuclear institute, we studied the effects of gamma radiation on the waterflea. We have observed that effect of gamma radiation o the methylation of DNA in the first generation of animals are transmitted to the subsequent unexposed generations of offspring (children and grandchildren). Studying the effects of radiation across multiple generations will give us a better insight into the effects of nuclear power plants and other sources of radiation on our ecosystems.



Scientific abstract

Our aim was to investigate epigenetic changes in Daphnia magna after a 25-day chronic external γ irradiation (generation F0 exposed to 6.5 μGy·h−1 or 41.3 mGy·h−1 ) and their potential inheritance by subsequent recovering generations, namely, F2 (exposed as germline cells in F1 embryos) and F3 (the first truly unexposed generation). Effects on survival, growth, and reproduction were observed and DNA was extracted for whole-genome bisulfite sequencing in all generations. Results showed effects on reproduction in F0 but no effect in the subsequent generations F1, F2, and F3. In contrast, we observed significant methylation changes at specific CpG positions in every generation independent of dose rate, with a majority of hypomethylation. Some of these changes were shared between dose rates and between generations. Associated gene functions included gene families and genes that were previously shown to play roles during exposure to ionizing radiation. Common methylation changes detected between generations F2 and F3 clearly showed that epigenetic modifications can be transmitted to unexposed generations, most likely through the germline, with potential implications for environmental risk.


Full reference (link):

Trijau, M., Asselman, J., Armant, O., Adam-Guillermin, C., De Schamphelaere, K., & Alonzo, F. (2018). Transgenerational DNA methylation changes in Daphnia magna exposed to chronic gamma irradiation. Environmental Science & Technology.