Usually, a mutation in the promoter region of an operon causes reduced levels of synthesis of the proteins encoded by that operon. Occasionally, a mutation in the promoter region actually causes increased levels of synthesis. Can you suggest (briefly) a plausible explanation?
2. A DNA sequence that may be present as only a single copy in a large mammalian genome can be amplified and cloned using the polymerase chain reaction (PCR). Describe the steps and reaction components required in a PCR experiment. Illustrate the steps in just one round.
3. Suppose a biochemist has just developed a technique for the efficient replacement of mutant genes with normal ones in human germ line cells. She proposes to use this technology to eliminate familial hypercholesterolemia from the human gene pool. Similar projects are being proposed in several other countries. Should the U.S. National Institutes of Health allow her to proceed? Why or why not?
4. What is a DNA microarray? How does it resemble and how does it differ from a DNA library?
5. Which would you expect to be larger, the percentage of the human genome that is translated into protein, or the percentage of the genome of a bacterium that is translated into protein? Why?