Is abundant A-to-I RNA editing primate-specific?

A-To-I RNA editing is common to all eukaryotes, associated with various neurological functions. Recently, A-to-I editing was found to occur abundantly in the human transcriptome. Here we show that the frequency of A-to-I editing in humans is at least an order of magnitude higher as that of mouse, rat, chicken or fly. The extraordinary frequency of RNA editing in human is explained by the dominance of the primate-specific Alu element in the human transcriptome, which increases the number of double-stranded RNA substrates.