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| Homework 8 | |||
Answer Key in PDF format
Bioc471a/571a Homework 8 - Due at the start of class October 30
1. (2 pts) What is the key advantage of the Brand and Perrimon Gal4 enhancer trap strategy over the original method described by Gehring's group? How is the recently described GeneSwitch version of the enhancer trap strategy even more versatile?
2. (3 pts.) What is the difference between methods used to improve crop plants incrementally through classical genetics, and the use of transgenesis to create super crops, i.e., can they lead to the same GMO if given enough time? What data supports the view that fields planted with Bt corn could lead to the demise of the Monarch Butterfly, what data refutes this contention? (use links in lecture notes).
3. (3 pts.) What would explain the lack of gene expression of a randomly integrated transgene in a founder mouse that tested positive by DNA analysis through several generations? What is the most likely explanation of no overt phenotype in a homozygous mouse KO, i.e., the KO mouse is normal despite loss of expression of the targeted gene? How is it possible to maintain a KO strain of mice in which the gene disruption is lethal?
4. (2 pts.) What is the advantage of the Cre-lox system for generating KO mice over the standard gene replacement strategy? Why doesn't the Cre recombinase protein cause DNA damage in mouse tissues in which it is constitutively expressed, e.g., in the brain of CaMKII-Cre founder mice as described in the lab practicum?
