Small RNAs in the Transgenerational Inheritance of Epigenetic Information

In recent years it has become evident that RNA interference-related mechanisms can mediate the deposition and transgenerational inheritance of specific chromatin modifications in a truly epigenetic fashion. Rapid progress has been made in identifying the RNAi effector proteins and how they work together to confer long-lasting epigenetic responses, and initial studies hint at potential physiological relevance of such regulation. In this review, we highlight mechanistic studies in model organisms that advance our understanding of how small RNAs trigger long-lasting epigenetic changes in gene expression and we discuss observations that lend support for the idea that small RNAs might participate in mechanisms that trigger epigenetic gene expression changes in response to environmental cues and the effects these could have on population adaptation.