Non-coding RNAs as the bridge between epigenetic mechanisms, lineages and domains of life

Many cases of heritable environmental responses have been documented but the underlying mechanisms are largely unknown. Recently, inherited RNA interference has been shown to act as a multigenerational genome surveillance apparatus. We suggest that inheritance of regulatory RNAs is at the root of many other epigenetic phenomena, the trigger that induces other epigenetic mechanisms, such as the depositing of histone modifications and DNA methylation. In addition, we explore the possibility that interacting organisms influence each other's transcriptomes by exchanging heterologous non-coding RNAs.