Double-stranded RNAs can be edited by ADARs by (a) selective or (b) promiscuous editing. (a) Short, imperfect dsRNA duplexes can be edited selectively at precise locations, which are determined by both the sequence and structure of the RNAs. When this occurs in mRNAs, the inosines (I) are translated as guanosines, thus generating proteins with altered amino-acid sequences. (b) Long perfect duplexes (over 30 bp) can be promiscuously edited, with up to half of the adenosines (A) on each strand being deaminated to I in an almost random fashion. These edited RNAs are not destined for translation in the cytoplasm; editing may lead to a number of distinct consequences.