The mapability of simulated sequences from the E. coli , A. thaliana , and human genomes. Mapping accuracy is shown on a Phred scale () for all three plots. Reads were simulated with base accuracies 1−ρ = 80%, 85%, … , 100%. In the fraction ρ of positions that are erroneous, we simulated 10% substitutions, 62% insertions, and 28% deletions. Missing values have no mismapped reads.