Although plant development is very different from animal development, there are many advantages to studying plants that can be brought to bear on basic research into developmental mechanisms. You have learned that a favorite model plant for developmental studies is Arabidopsis thaliana. To learn more about some of the benefits of working with plants, go to the Schiefelbein Lab homepage at the University of Michigan: http://www.mcdb.lsa.umich.edu/labs/schiefel/ and explore the following questions:

• Why do they feel that their system, the determination of hair versus non-hair cells in the epidermis of the Arabidopsis root, is such a great system for study of developmental processes? Using the Wolpert text, and other sources, review the anatomy of the plant, and the development and histology of human epidermis. Contrast the advantages of the Arabidopsis system to the disadvantages of forming human epidermis.
• Following the link "What We Have Learned", and study their model for hair (H) versus non-hair (N) cell determination. Summarize this model in your own words. What kinds of proteins are produced by the genes shown in the figure of their model? What do these proteins tell you about Arabidopsis development?
• Their model predicts that differences in the levels or activities of WER and CPC lie at the heart of the determination mechanism. Can you imagine a model for how these differences might be established? If you’re stumped, think about "lateral inhibition" (see Figure 11.17 in Wolpert book).