Fig. 2. Comparison of the Tribolium, Drosophila, and Anopheles achaete-scute complexes. (Top) The Tribolium ac/sc complex contains one proneural ac/sc gene, Tc-AS and one asense homolog, Tc-ase, that reside 55 kb apart. Cytochrome P450 (cyt P450) lies downstream of Tc-ase. (Middle) The Drosophila ac/sc complex contains three proneural genes ac, sc and l'sc and one asense gene located 45 kb downstream of l'sc. As in Tribolium, cyt P450 resides downstream of ase. (Bottom) The Anopheles ac/sc complex contains one proneural gene, Ag-ASH, and one asense gene, Ag-ase, that reside 22 kb apart. Unlike Tribolium and Drosophila, cyt P450 lies between the Anopheles ac/sc genes. Proneural genes are in shown in blue, asense genes in red, and cyt P450 in black. Arrows denote the direction of transcription. Drosophila map is adapted from Campuzano et al. (Campuzano et al., 1985) and the Anopheles map was constructed from available genome sequence data (Holt et al., 2002).