Transposable elements in the tree shrew are targeted not only by piRNAs but also by smaller RNAs resembling typical features of siRNAs.
Comprehensive bioinformatic analyses showed that piRNAs preferentially target transposon transcripts at sites that do not form foldback
structures and thus remain accessible for guiding piRNAs. In contrast, sites that avoid piRNA targeting owing to strong secundary structures
are processed by Dicer, an enzyme that recognizes double-stranded RNA (