B250 examination 2003

 Answer FOUR questions

 1. Answer ONE of the following:

a) Describe how the segmented body plan of the Drosophila embryo is established.

b) Describe the structure and function of the Bithorax and Antennapedia complexes in fruit flies.  How do they relate to the Hox gene clusters in vertebrates?

2. Write an essay on anterior-posterior and dorsal-ventral patterning in the vertebrate central nervous system.

3. Describe pre-implantation mouse development. Then write notes on TWO of the following:

a) generating transgenic mice by egg injection

b) knocking out genes in embryonic stem (ES) cells

c) using embryonic stem (ES) cells to generate chimeric mouse embryos

4. Sex evolved a long time before the divergence of fruit flies and humans, yet the sex-determining mechanism seems, at first sight, to be completely different in these two species.  How can this apparent paradox be resolved?

5. Describe the changes that occur in the oocyte during maturation and fertilization in different species of animals.

6. Write an essay on vascular development.

7. How do vertebrate limbs develop?

8. Discuss the role of the vegetal hemisphere in amphibian mesoderm formation.