For 10 points, name this process in which Dicer and small pieces of the namesake nucleic acid regulate gene expression by preventing transcription.
ADAR enzymes, which de-aminate adenosines to inosines, suppress the activity of many enzymes involved in this process. Although scientists increased expression of chalcone synthase, this process caused a decrease of pigmentation in petunias. One intermediate in this process is a 70 base-pair long stem-loop region, which is produced by a complex of DGCR8 to Drosha. That intermediate is cleaved into a structure with a passenger strand and a guide strand, the latter of which is selected by Argonaute to form the Risc complex. The 2006 Nobel Prize was given to Fire and Mello for studying this process in the worm C. elegans.  For 10 points, name this process in which Dicer and small pieces of the namesake nucleic acid regulate gene expression by preventing transcription.
ADAR enzymes, which de-aminate adenosines to inosines, suppress the activity of many enzymes involved in this process.
RNA interference or RNAi [prompt on "interference"]