Fig. 6
Cells synchronized in S phase in newest segment while the anterior growth zone has few cells in S phase. a, b After 30 min of exposure to EdU, a band of cells in S phase is visible (green) in the last added segment (red arrows indicate last two En stripes) in Thamnocephalus. This pattern is maintained throughout the early stages as seen in representative 1 h (a) and 2 h (b) larvae. The band lies almost entirely within the last segment after En segment specification. c, d In both 1 h (c) and 2 h (d) larvae, cells in the last added segment (EdU band, light green) do not show pH3 staining (pink) indicative of M-phase. Anterior growth zone is indicated by yellow bars; posterior growth, blue bars. Scale bars equal 100 μm