Repeat-associated small-interfering RNAs (rasiRNAs) account for90-95% of the global small RNA population in all plant species. Astheir name suggests, rasiRNAs are derived from the various classesof repetitive DNA that constitute more than 95% of the entirenuclear genome sequence of a plant. The rasiRNAs keep the majorityof the repetitive DNA in an inactive state. State; (1) theDNA-dependent RNA polymerase(s) involved in rasiRNA precursortranscript transcription; (2) whether rasiRNA precursors aremolecules of perfectly or imperfectly structured double-strandedRNA (dsRNA); (3) the DICER-LIKE (DCL) endonuclease(s) responsiblefor rasiRNA production; (4) the size of rasiRNAs, and; (5) themechanism of RNA silencing directed by rasiRNAs in order tomaintain repetitive DNA in an inactive state.
