Figure 13

Segment polarity gene-like intrasegmental expression. The slime-papillae-bearing segment is represented (broad black lines) in embryos older than stage 10. The positions of the slime papillae are indicated by transverse broad black lines. Thin black lines mark intrasegmental borders of Wnt gene expression. The grey circle marks the position of the salivary gland. Arrows point to the position of the parasegment boundary and the two possible positions of the segmental boundary. Expression of Wnt genes is indicated by coloured bars. Positions of expression of the segment polarity genes engrailed (en) and hedgehog (hh) are indicated by dark grey (co-expression of en + hh) and light grey (expression of en) bars. Drawing is out of scale. PSB, parasegment boundary; SB?, possible position of segmental boundary; sg, salivary gland.