The sequence of images at the right is a computer morph of still images of
Xenopus zygotes labeled with the fluorescent dye trypan blue to visualize yolk platelets
during the 60 min period after fertilization (Danilchik and Denegre, 1991).
Development 111, 845-856). Since it is a morph, the dynamics should
not be taken too literally. Nevertheless, the sequence does demonstrate
the dynamic changes in the deep
cytoplasm of the animal
pole that result from subcortical
rotation movements. For reference, the future ventral side
of the embryo is on the left. This is also the side where the
sperm
entry point (SEP) is visible after fertilization.