RNA Editing Differences occur between nucleotides encoded within DNA and the RNAs transcribed from these sequences. Such RNA editing can lead to changes in the amino acid composition of resulting proteins, and the removal of editing can have pathological consequences. Examining the occurrence of A-to-I editing in coding and noncoding RNA transcripts in 13 Drosophila species, Zhang et al. recorded the origin, loss, and maintenance of edited sites across the species. They found that editing can affect gene expression and that sites in both coding and noncoding sequences could be under evolutionary selection to maintain editing. In addition, RNA editing in the 3′ untranslated region of genes may contribute to mRNA degradation and may be a mechanism by which transcript levels are regulated. PLOS Genet. 13 , e1006563 (2017).