Module 8: Figure convergent extension
Convergent extension during vertebrate gastrulation and neurulation.
During gastrulation, the developing masses of cells polarize in the medial–lateral plane and then begin to converge on each other. By attaching and pulling on each other, they become elongated, and then through a process of intercalation, the embryo begins to lengthen. The appearance of the zebrafish embryo at the end of this process of convergent extension is shown in panels i and j in Module 8: Figure PCP in insects and vertebrates.