. "The chemical reactions and pathways resulting in the breakdown of piRNAs, Piwi-associated RNAs, a class of 24- to 30-nucleotide RNA derived from repeat or complex DNA sequence elements and processed by a Dicer-independent mechanism." . . . "piRNA catabolic process" . "piRNA breakdown" . "piRNA catabolism" . "piRNA degradation" . "Piwi-associated RNA catabolic process" . .