The comparative frequency of variants across the rRNA locus. The proportion of sites that vary from the consensus rRNA sequence is shown for B. tryoni (blue), B. neohumeralis (yellow) and B. jarvisi (red). Variation was measured from the consensus sequence for that species. The consensus sequence for B. jarvisi is only 9498 bp (rather than 10 kb) due to shorter assembled IGS sequences. The bar below the graph indicates the rRNA unit, with the four rRNA loci shown in black. The limits of the four rRNA loci are based on the D. melanogaster sequence. IGS = intergenic spacer (incomplete), ETS = external transcribed sequence, ITS1 and 2 = internal transcribed sequences.