1. What is one big difference between how frogs and fishgastrulate? (1-2 sentences) (Hint -explain how each of theseorganisms gastrulates and the difference will be obvious!)
2. Number the following steps of germ cell development in theappropriate order.
A. The primordial germ cells undergo meiosis.
B. The primordial germ cells are specified
C. The primordial germ cells migrate to where the gonads aredeveloping
3.
What are the signals that are required for the induction of theorganizer?
| | TGF-beta signaling is the mesoderm inducing signal, Wntsignaling comes from the Niewcoop center |
| | Wnt signaling is the mesoderm inducing signal, TGF-betasignaling comes from the Niewcoop center |
| | Signals come from the animal hemisphere to induce theorganizer |
| | the organizer is autonomously specified |
4. How did C. Easley make sperm-like cells from human foreskinfibroblasts? (2-3 sentences)
5. What is special about how the genes (whose mutations resultin the flies above) are arranged in the fly genome and how they areexpressed in the developing embryo? (1-2 sentences)
