FIGURE 2. Gene models in 12 Drosophila genomes.

Number of gene models that fall into one of five homology classes: single-copy orthologues in all species (single-copy orthologues), conserved in all species as orthologues or paralogues (conserved homologues), a D. melanogaster homologue, but not found in all species (patchy homologues with mel.), conserved in at least two species but without a D. melanogaster homologue (patchy homologues, no mel.), and found only in a single lineage (lineage specific). For those species with expression data²⁹, pie charts indicate the fraction of genes in each homology class that fall into one of four evidence classes (see text for details).