Fig. 9. Comparison of external and internal phenotypes observed in sibling and Wnt11 family morphants.

Top panel shows the vegetal view of the embryos with the externally visible phenotype, and the bottom panel shows cartoons of a cross sectional view with internal events indicated. A. During Stage 10.5, we observe the dorsal blastopore lip moving vegetally (upper panel, purple). This is due to epiboly (bottom panel, pink) and vegetal rotation (bottom panel, blue) that move the marginal zone mesendoderm deeper in the embryo (bottom panel, orange). B. During Stage 11, we observe the dorsal blastopore lip continuing to move vegetally (upper panel, purple), and the vegetal material moves animally and dorsally under the dorsal blastopore lip. The blastopore lip movement is now largely due to convergent extension (bottom panel, green). Continuing vegetal rotation movements (upper panel, blue) drive the vegetal material under the dorsal blastopore lip. The archenteron has extended and bottle cells remain at the animal extent. C. In the Wnt11 family morphants, we observe moderate vegetal movement of the dorsal blastopore lip (upper panel, small purple arrow) before and during Stage 10.5, and very little after Stage 11. The vegetal material does move animally and dorsally (upper panel, brown arrow) and over-flows the dorsal blastopore lip. We also observed that the archenteron does not extend, and the bottle cells remain at the surface of the embryo. The dashed lines indicate processes that are likely affected by knockdown of the Wnt11 family ligands (convergent extension - green, vegetal rotation - blue).