PRGs identified by gene movement between chromosome arms. (A) Observed PRG counts across the Drosophila phylogeny. The set of 478 one-gene PRGs (Table 1) have been traced to events at various nodes of the phylogeny. (*) For the 67 PRGs at the genus root, ancestral states could not be determined. Five PRGs could not be placed unambiguously. (B) Multigene PRG relocation. Phylogenetic analysis of the original and new genomic location of this multigene PRG supports a DNA-based movement hypothesis. (†) There is a duplication of the gene yellow-f(f2) adjacent to the PRG relocation. Intron-exon structures are not shown. There are additional context changes in some species (D. persimilis, D. pseudoobscura).
