Figure 3.
Nucleotide substitution rates for the core and expansion regions of the 18S and 28S genes. Divergence between sequences was calculated as the number of differences per aligned sequence (indels were not considered). Species pairs for which divergence was calculated were simulans vs. sechellia; melanogaster vs. each of sechellia, yakuba, ananassae, pseudoobscura, willistoni, and virilis; and finally, virilis vs. each of mojavensis, grimshawi, willistoni, and pseudoobscura. The species divergence times were those obtained from the Drosophila Species Genomes Web site (http://insects.eugenes.org/species/).
