During embryonic development, Dpp is uniformly expressed at the dorsal side of the embryo, establishing a sharp concentration gradient. In the imaginal discs, Dpp is strongly expressed in a narrow stripe of cells down the middle of the disc where the tissue marks the border between the anterior and posterior sides.
During embryonic development, Dpp is uniformly distributed on the dorsal side of the embryo, creating a distinct concentration gradient. In the imaginal discs, Dpp is strongly expressed in a narrow band of cells running down the middle of the disc, which demarcates the boundary between the anterior and posterior sides.