from Mario A. Arteaga-Vazquez and Ana E. Dorantes-Acosta writing in Epigenetics: A Reference Manual:
Paramutation is a fascinating phenomenon in which epigenetic information can be transmitted through trans-interactions between one allele of a gene to another allele or between homologous DNA sequences that establishes a state of gene expression that is heritable for generations. Paramutation was discovered in maize and similar phenomena have been described in other plants, fungi and animals. In this chapter, we describe several classic plant paramutation systems and discuss recent advances that implicate a role for RNA and a number of components of an RNA-based transcriptional silencing pathway on paramutation.
Further reading: Epigenetics: A Reference Manual