RNA interference can be heritable, which means that it can have transgenerational effects [Burton et al. 2011]. Responsible for this appears to be piwi-interacting RNAs (
piRNAs) [Brennecke et al. 2008; Grentzinger et al. 2012]. piRNAs are slightly longer than microRNAs and associated with RNA-protein complexes, mediated by the binding to Piwi proteins. piRNAs represent a much bigger class of non-coding RNA than microRNAs. piRNAs are associated with gene silencing, most especially at repeat elements like transposons [Aravin et al. 2008]. piRNAs are important in the germline, where they can aid in establishing other epigenetic patterns like DNA methylation and histone modifications. The expression of piRNA is downregulated during aging in C. elegans [Kato et al. 2011].
Burton NO, Burkhart KB, Kennedy S. Nuclear RNAi maintains heritable gene silencing in Caenorhabditis elegans. Proc. Natl. Acad. Sci. U.S.A. (2011).
Brennecke J, Malone CD, Aravin AA, Sachidanandam R, Stark A, Hannon GJ. An epigenetic role for maternally inherited piRNAs in transposon silencing. Science. 322(5906), 1387–1392 (2008).
Grentzinger T, Armenise C, Brun C, et al. piRNA-mediated transgenerational inheritance of an acquired trait. Genome Res. (2012).
Aravin AA, Sachidanandam R, Bourc'his D, et al. A piRNA pathway primed by individual transposons is linked to de novo DNA methylation in mice. Mol. Cell. 31(6), 785–799 (2008).
Kato M, Chen X, Inukai S, Zhao H, Slack FJ. Age-associated changes in expression of small, noncoding RNAs, including microRNAs, in C. elegans. RNA. 17(10), 1804–1820 (2011).