Developmental role of dpp in the gastropod shell plate and co-option of the dpp signaling pathway in the evolution of the operculum

► Dpp is required for expressions of chitin synthase 1 and grainyhead in shell field margin. ► Knockdown of dpp led to suppression of cell proliferation in the mantle edge. ► Dpp is essential for operculum development and grainyhead expression. ► Co-option of dpp-grainyhead pathway may have contributed evolution of the operculum.