Microplastic fiber-induced transgenerational epigenetic disruption impairs fitness in Daphnia magna.

Microplastic fibers (MPFs) are the most prevalent type of microplastics in freshwater environments. However, although the effects of plastic pollution on various aquatic species have been extensively studied, the underlying mechanisms of the intergenerational effects of MPFs on aquatic organisms remain poorly understood. Here, we investigated the multi- and transgenerational toxicity of MPFs in Daphnia magna over three generations. Our findings revealed that MPFs exposure negatively affects reproduction and molting frequency across generations. Notably, the transgenerational groups exhibited reproductive impairments and reduced molting frequency in the F1 and F2 generations (F1T and F2T), despite never being directly exposed to MPFs. Furthermore, whole-genome bisulfite sequencing revealed that these transgenerational adverse effects are associated with differential DNA methylation patterns in specific genes, suggesting that MPFs may threaten Daphnia populations through epigenetic modifications. Collectively, our findings provide valuable insights into the intergenerational toxicity of MPFs and the underlying molecular mechanisms driving these responses.