Fig. 2.

Phylogenetic relationship among the species studied based on ref. 33. All species belong to the Drosophila genus, except S. lebanonensis from the Scaptodrosophila genus. Karyotypes are indicated, F element fused to X (F+X), F element as a unique dot chromosome (F, X), and F element fused to an autosome (F+A). POF bindings are tested in both sexes and indicated if sex-specific. The F element specificity is always seen in both sexes. No, No staining is detected. The indicated stainings for MSL and H4K16ac are specific for the male X. Results in italics have been shown (11, 31, 45).