RNA editing usually affects only a fraction of expressed transcripts and there 
is a vast amount of variation in editing levels of ADAR (adenosine deaminase, 
RNA-specific) targets. Here we explore natural genetic variation affecting 
editing levels of particular sites in 81 natural strains of Drosophila 
melanogaster. The analysis of associations between editing levels and 
single-nucleotide polymorphisms allows us to map putative cis-regulatory regions 
affecting editing of 16 A-to-I editing sites (cis-RNA editing quantitative trait 
loci or cis-edQTLs, P < 10(-8)). The observed changes in editing levels are 
validated by independent molecular technique. All identified regulatory variants 
are located in close proximity of modulated editing sites. Moreover, colocalized 
editing sites are often regulated by same loci. Similar to expression and 
splicing QTL studies, the characterization of edQTLs will greatly expand our 
understanding of cis-regulatory evolution of gene expression.