Fig. 2. Summary diagram of marker genes expressed in brain NBs of wild-type and vnd mutant embryos at stages 9 and 11. (A-D) The schemes represent NB maps of one hemibrain: anterior (a) is towards the top, posterior (p) is towards the bottom, dorsal (d) is leftwards, ventral (v) is rightwards. Numbers and distribution of NBs correspond to the situation in flat preparations of wild-type embryos at stage 9 (A,B,B') and stage 11 (C,D,D'). The color code indicates expression of the genes investigated in this study in individual brain NBs. Broken blue lines enclose the domain of Vnd expression and, accordingly, the population of ventral NBs; broken red lines mark neuromeric boundaries between TC, DC and PC. (A,C) Wild type (wt). (B,B',D,D') vnd embryos (vnd-); individual NBs encircled with broken black lines are absent to a certain degree. (B',D') The frequencies of their presence (in %) are indicated at stage 9 for all NBs, at stage 11 for all NBs in the TC, DC and all ventral and adjacent dorsal NBs in the PC. NBs (grey) develop within the Vnd domain. (B,D) Expression of a marker is indicated as missing if it is not detected in more than 90% observed cases. Hatched colors indicate ectopic gene expression. As the exact identity of NBs that ectopically express msh, ems and dac is not clear, hatched NBs represent potential candidates, of which only a subfraction will normally be found to express the respective marker. For further details, see text.