Problem
The Dorsal-Ventral Axis of Xenopus and Fruit flies are inverted.
1. A.Using the Dorsal-Ventral Signalling pathways explain how this axis is inverted between the two organisms. Indicate which of the factors are homologs between Drosophila and Xenopus.
2. Thinking of the "Four Signal Model" in Xenopus describe the effect of injecting chordin morpholinos into the ventral blastomeres of a UV-treated frog egg that had been "tipped" on the four signals. Explain your reasoning.