Fig. 16

Morphogenesis of the blastopore lip. a–e Vegetal/ventral views during gastrulation with the future anterior at the top of the figure. Time points are the same as those shown in rows 2–6 in Figs. 1 and 14: a ~94 hpf, b ~99 hpf, c ~120–130 hpf, d ~130–137 hpf, e ~140–145hpf. The coloring shows the relative clonal contributions of cells within the embryo and to the blastopore lip. The blastopore lip is marked in each panel by a solid white line. The blastopore lip marks the boundary between the ectodermal micromere cap and the endoderm/endomesoderm/ectomesoderm. As gastrulation proceeds, some cells leave the blastopore lip, but remain on the surface, and these are marked by a dashed white line. The 2d cells are marked by a dashed yellow line in a, b, but are more difficult to follow in time points c–e and thus are not shown. The 3c²- and 3d²-derived terminal cells (TC) are marked with an asterisk to follow their migration after they leave the blastopore lip. Some cells of the blastopore lip move internally into the blastocoel/archenteron, and the solid white line can no longer be seen in some areas d, e. bp blastopore, em ectomesoderm (derived from 3a² and 3b²)