Fig. 6
From: Small RNAs mediate transgenerational inheritance of genome-wide trans-acting epialleles in maize
Transgenerational inheritance of hybrid-induced RdDM loci in backcrossing and selfing generations. Left panel, inbred parents (P1 and P2) have differential methylation patterns on the promoter of a gene. These loci are maintained by siRNAs via RNA-directed DNA methylation (RdDM) pathway. Hybridization triggers trans-acting of siRNAs to induce trans-chromosomal methylation (TCM) and demethylation (TCdM) loci in the F1 hybrid (middle panel). Note that siRNAs and gene expression are depicted only in one strand. Right panel, some of these F1 TCM and TCdM loci that acquired from the donor parent are heritable, like paramutation through multiple backcrossing to the recurrent parent and self-pollination due to presence of siRNAs. As a result, these transgenerational DMRs (tgDMRs) affect expression of adjacent genes (epigenes or epialleles) involved in different biological pathways including stress responses to regulate growth and adaptation in plants