Abstract

The most recent work toward compiling a comprehensive database of adenosine‐to‐inosine RNA editing events suggests that the potential for RNA editing is much more pervasive than previously thought; indeed, it is manifest in more than 100 million potential editing events located primarily within Alu repeat elements of the human transcriptome. Pairs of inverted Alu repeats are found in a substantial number of human genes, and when transcribed, they form long double‐stranded RNA structures that serve as optimal substrates for RNA editing enzymes. A small subset of edited Alu elements has been shown to exhibit diverse functional roles in the regulation of alternative splicing, miRNA repression, and cis‐regulation of distant RNA editing sites. The low level of editing for the remaining majority may be non‐functional, yet their persistence in the primate genome provides enhanced genomic flexibility that may be required for adaptive evolution.