Figure 2

Evolution of experimental blastomere growth observed on feeder cell layer on culture days 2, 3, and 4. Top row shows a single blastomere undergoing cleavage (a) and forming a "unilaminar vesicle" on day 3 (b). Cellular arrest and degeneration were evident by day 4 (c). Bottom row shows another cleaving blastomere (d), which formed a cellular aggregate on day 3 (e) and later developed an inner cell mass-like structure (f).