Skip to main content
Figure 4 | EvoDevo

Figure 4

From: How the pilidium larva grows

Figure 4

Color-coding of relative BrdU retention, same dataset as Figure 3D: 20-day-old pilidium labeled with six-hour BrdU treatment on day 6. (A) The near half (projection of 45 0.8-μm sections); (B) a slab of five sections cutting through the cephalic imaginal disc (dashed outline). Confocal data was coded in Hue/Saturation/Brightness by calculating the simple ratio of Hoechst fluorescence to BrdU antibody fluorescence; the resulting images were used as the ‘Hue’ channel, running from red through green, whereas the original Hoechst image was used as the ‘Brightness’ channel. The ‘Saturation’ channel was full white. Consequently, all nuclei are shown, and redness indicates how much BrdU each nucleus retains. In other words, a green nucleus is one that either never incorporated any BrdU, or that diluted it to extinction through division; yellow nuclei clearly had an ancestor that was labeled during the BrdU pulse, but have since divided and diluted the label. The presence of many yellow and green nuclei in the cephalic disc, an organ which did not exist at the time of pulse labeling, shows not only that imaginal discs descend from axils, but that they include cells that divide enough to dilute BrdU to extinction.

Back to article page