Alterations to the parental genome (aqua arrow) or environmental stimuli (green arrow) could trigger epigenetic changes in the germline of the organism that could be transmitted to the next generation. Such epigenetic changes could possibly be relayed or amplified in the germline of subsequent generations, and persist for several generations. Eventually, epigenetic changes would be reset to a basal state. So far, the epigenetic mechanisms that have been described include changes to chromatin (histone marks, DNA methylation) and changes to non-coding RNAs, in particular those involving the nuclear RNAi pathway. An amplification loop could be initiated by alteration in chromatin marks (e.g. H3K9me3) at a genomic locus, followed by the generation of non-coding RNAs at this particular locus, which would then be transmitted via the germline, and in turn guide H3K9me3 deposition at that same genomic locus in the germline of the next generation. In grey are additional potential mechanisms that remain to be investigated ().