270 CHAPTER 30 



QUESTIONS FOR DISCUSSION 



30. 1 . In what way does the study of genes help us understand normal embryonic develop- 

 ment? 



30.2. If most somatic cells have the same genetic content, why do different cells differentiate 

 in different ways? 



30.3. In what ways can genes regulate embryonic development? 



30.4. Do the studies of Creeper, of Brachy, or of pituitary dwarfism in mice offer any 

 support for the view that most, if not all, genes have a single primary effect? 



30.5. What is the relationship between phenogenetics, developmental genetics, physiological 

 genetics, and biochemical genetics? 



30.6. Discuss the comparative importance of genes that act earlier, as compared with those 

 which act later, in development. 



30.7. Do you suppose that all genes act at all times in all cells of the body? Why? 



30.8. "This Chapter tells more about development than it does about genes." Do you 

 agree? Why? 



