The dorsal lip is a critical structure in embryonic development, particularly in amphibians like the Xenopus laevis frog. It is located at the upper edge of the blastopore, which is the opening that forms during the early stages of gastrulation. The dorsal lip plays a key role in organizing the development of surrounding tissues and is essential for the formation of the mesoderm layer. During gastrulation, the dorsal lip initiates the process of invagination, where cells move inward to form different layers of the embryo. This structure is also involved in the signaling pathways that guide the differentiation of cells into various tissues, making it vital for proper embryonic development and the establishment of body axes.