Early expression of Apis genes likely to be involved in DV patterning. (A) Am-Dpp is expressed weakly through the posterior two-thirds of a stage 4 embryo. (B) By stage 4 Am-Dpp RNA expression is found at the anterior and posterior pole and absent from the central region of the embryo. (C) Am-tkv mRNA is found at throughout the posterior half of the embryo. (D) After commencement of gastrulation, Am-tkv mRNA is strongly upregulated in an anterior domain and a weaker posterior terminal domain. (E) Expression of Am-sog is first detected at stage 7 on the ventral side of the embryo in a segmented pattern corresponding to development of the nervous system. (F) RNA for Am-pnr is weakly detected in young embryos and was not strongly detected until stage 9, in cells lining the yolk cavity (G). (H) Am-Toll mRNA is detected throughout the early stage 3 embryo in a pattern suggesting that it is in association with energids. (I) By stage 4, Am-Toll is expressed in distinct regions along the ventral surface of the embryo. (J) mRNA for Am-sna and Am-twi (K) are detected through the ventral ectoderm, where the prospective neuroectoderm will form. (L) AmNk2.2 mRNA is expressed in a layer of cells located at ventral ectoderm folds during gastrulation. These cells will later fuse at the mid-line to contribute to the neuroectoderm. (M) Am-spz is expressed throughout the developing embryo (stage 4 shown). All embryo images are oriented with anterior to the left and dorsal side up.