Fig. 6. Evolution of the cortex from fertilization to the eight-cell stage. Recapitulative diagram showing the rearrangements of the plasma membrane, adhering cER network and associated postplasmic/PEM RNAs (cER/mRNA), and microtubules from fertilization to the eight-cell stage. An oocyte, zygotes during the first and second major phases of reorganization, and an embryo at the eight-cell stage are represented in cross section and as isolated cortices in surface view and enlarged cross section.