Fig. 7

Expression of ptSoxC-1. Flat-mounted embryos at different stages of development after RNA in situ hybridization. a) ptSoxC-1 is strongly expressed in the most anterior region of the presumptive neuroectoderm at stage 6 (white arrow). b) At stage 8.2, strong expression is observed in the ventral nerve cord (white arrows) with the exception of the most posterior part of the SAZ (black arrowhead) c) At stage 9.1, expression is apparent in clusters of cells in the head and each anterior segment until the third opisthosomal segment (O3): white arrows indicate localized expression. The signal in the limb buds is background and staining at the most posterior part of the O5 segment is an artefact of incomplete chorion removal. Ch: chelicerae, L1 – L4: prosomal segments 1 to 4, O1 – O4: opisthosomal segments 1 to 4, Pp: pedipalps; SAZ: segment addition zone. Ventral views are shown for all embryos with the anterior to the left. Scale bars: 150 μm