Chapter 18, Problem 10P

Some people are concerned about the possible health consequences of eating acrylamide, a by-product of frying potatoes with a high content of the amino acid asparagine. The U.S. FDA recently approved for human consumption GM potatoes that make less asparagine than normal potatoes. These potatoes express RNA interference (RNAi) transgenes that lower the amounts of two different enzymes in the asparagine synthesis pathway, called StAs1 and StAs2.

a.	Diagram the transgenes that could be used to reduce the expression of the StAs1 and StAs2 genes and explain how they work. (Recall from Chapter 17 that RNAi is initiated by double-stranded RNAs.)
b.	Why is it important that the RNAi transgene lower the levels of StAs1 and StAs2 gene expression but do not eliminate expression of either gene entirely?
c.	Scientists have recently made transgenic potatoes expressing an RNAi insecticide that kills the Colorado potato beetle, a pest of this crop. Speculate about the kind of transgene that might have been involved and the advantages of this approach.