Fig. 4

Expression of Wnt1 genes in spiders. Expression of Wnt1 in Parasteatoda (A–D), Pholcus (E–H), and Acanthoscurria ((I–L (Wnt1.1), M, N (Wnt1.2)). In all panels, except panel O, anterior is to the left. Ventral views, except panels C, D, F and H (lateral views). Developmental stages are indicated. Filled circles (•) in panels C and D mark expression along the dorsal rim of the prosoma. Asterisks in panel E mark the center of the germ disc (the later posterior region of the germ band). Asterisks in panels D and H mark dorsal stripes of expression. The arrow in panel C points to the book lung that expresses Wnt1 in the form of three separate domains (cf. inlay in panel C). Panels indicated with an apostrophe (´) represent SYBR-green stained embryos corresponding to the embryo shown in the panel without apostrophe. Expression patterns are summarized in panel O, anterior is up. Abbreviations: ch, chelicera; L, leg; lr, labrum; m, mouth; O, opisthosomal segment; pc, pre-cheliceral region; pp, pedipalp; saz, segment-addition zone; sp, spinneret