The toolkit and generating form

Readings: Chapters 3-4 from “Endless Forms Most Beautiful”

Informational Questions (bring your answers to these questions, as you will be responsible for answering one of them at the start of class):

1. What makes our red blood cells, muscle cells, and neurons different from each other? Give specific examples.

2. Do different cell types have the same DNA? What data would support this idea?

3. How does the lac repressor act to control the expression of beta gal RNA? Draw a diagram illustrating the mechanism including the switch DNA, the lac repressor, and the beta gal gene.

4. What is gene logic and what are its two major features? How do they relate to switches and transcription factors?

5. What is the function of eyeless in Drosophila and Aniridia in humans? How do eyeless and Aniridia work?

6. What is the “tool kit” of animal development? How do the tools work? Give examples of tool kit genes.

7. What experiment(s) supports Sonic hedgehog functioning as the active molecule in the ZPA?

8. What do the Hox genes do?

Discussion Questions (we will consider these questions in class after talking about the Informational Question above) as a way to apply and explore the ideas presented in the reading):

9. (Group 1) In what way are the Hox genes similar between flies and mice? What do you think this suggests about Hox gene functional similarities in these two very different organisms?

10. (Group 2) In what ways is the following statement true “What is true for E. coli is true for elephants”. Is the converse “What is true for elephants is true for E. coli” true?

11. (Group 3) Why do you think the mouse small eye gene results in a fly eye, and not a mouse eye, when expressed in the fly?

12. (Group 4) Do you think that the “tool kit” of animal development constrains animal form? That is, can the “tool kit” give rise to infinite types of form?