This review discusses two modes of convergent extension (CE), the crawling and the contraction modes, and summarizes cell movements elicited by cytoskeleton dynamics, the participation of cell adhesion molecules, and the involvement of upstream regulatory molecules for each mode. Notochord formation in Xenopus laevis embryos has been one of the pioneering model systems of CE, thus the findings from the studies of X. laevis are mainly focused to approach the biological question of collective cell movement.

Key developmental mechanisms such as co‐option, heterochrony, and genetic cascades govern the evolution of adaptive butterfly wing patterns.

Post‐transcriptional regulation controls progenitor proliferation, neuronal differentiation, and migration, impacting all stages of corticogenesis.

Summary of the known otocyst transcription factors regulated by crosstalk among three families of secreted proteins during dorsoventral (DV) patterning. DV patterning of the otocyst is orchestrated by crosstalk among three families of secreted proteins that regulate the expression of transcription factors in a temporospatial manner. BMP signaling, which is required for the development of the dorsal (vestibular) component of the inner ear, upregulates the expression of two transcription factors, Dlx5 and Hmx3, both of which are essential for vestibular development. WNT and BMP signaling partner to induce Dlx5 expression in the dorsolateral wall of the otocyst, whereas WNT signaling acts alone in the dorsomedial wall to regulate the expression of Gbx2, which in turn seems to be required for Dlx5 expression. SHH signaling, which is required for the development of the ventral (cochlear) component of the inner ear, upregulates the expression of two transcription factors, Pax2 and Otx2, both of which are essential for cochlear development. The expression of transcription factors in the dorsal and ventral otocyst also is inhibited by secreted factors, with BMP signaling downregulating Otx2 expression and SHH signaling downregulating Hmx3 expression and arguably downregulating Dlx5 expression.