Yukiko Shimada, Fabio Mohn, and Marc Bühler at the FMI elucidated an important mechanistic detail of small RNA mediated chromatin silencing. They showed in fission yeast that the small RNA in the RNA induced silencing complex (RISC) interacts with nascent transcripts and not with complementary DNA to induce heterochromatin formation. In addition, both the transcription rate and transcript processing have an impact on the silencing process.