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B250 Biology of Development 2002

Answer FOUR questions. All questions carry equal weighting.

1. What roles do the anterior visceral endoderm (AVE) and the node play in organising the anterior-posterior axis (head and trunk) of vertebrates? Describe experiments that identified genes that are involved in this process in mice and frogs.

2. Describe what is known about the genes that determine sex in humans.  How does the human sex determination pathway compare with that in         other species?

3. What roles do the specific structures of the spermatozoa and oocyte play in fertilization?

4. Write an essay on the development of the vasculature in vertebrates.

5. Describe the events involved in mesoderm induction in Xenopus and, in particular, the role of the gene Xnr1.

6. Describe how the Drosophila embryo becomes segmented.

7. Write about the homeotic (HOM) gene complexes of Drosophila and their vertebrate equivalents.

8. Describe how the vertebrate nervous system is patterned along the anterior-posterior and dorsal-ventral axes.

END OF PAPER

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