Gastrulation

The coordinated rearrangements that establish the principal germ layers and their relative positions in an early embryo.

Spreading and thinning of a tissue to cover a larger area of the embryo, often requiring intercalation and forces generated by adjacent tissues.

A superficial epithelial cell layer of the zebrafish embryo that spreads over the yolk during epiboly.

An extraembryonic syncytial domain in teleost embryos that generates forces and signalling inputs affecting gastrulation.

Rolling of a tissue over an embryonic margin, followed by internal movement. It differs from individual-cell ingression.

Bending of a tissue sheet inward while retaining substantial epithelial continuity.

Internalization of individual cells from a surface tissue, often involving an epithelial-to-mesenchymal transition.