Week 7 Assignment
Please thoroughly answer the following 5 questions.
1. Describe how you could produce many copies of β-globin cDNA from the rat using reverse transcriptase-PCR.
2. Several research studies are under way that involve the use of gene therapies to inhibit the growth of cancer cells. As discussed in Chapter 23, oncogenes are mutant genes that are overexpressed and cause cancer. New gene therapies are aimed at silencing an oncogene by producing antisense RNA that recognizes the mRNA transcribed from an oncogene. Based on your understanding of antisense RNA (described in Chapters 16 and 17), explain how this strategy would prevent the growth of cancer cells.
3. A person with a rare genetic disease has a sample of her chromosomes subjected to in situ hybridization using a probe that is known to recognize band p11 on chromosome 7. Even though her chromosomes look cytologically normal, the probe does not bind to her chromosomes. How would you explain these results?
4. Figure 21.2 describes the technique of FISH. Why is it necessary to “fix” the cells (and the chromosomes inside of them) to the slides? What does it mean to fix them? Why is it necessary to denature the chromosomal DNA?
5. With regard to DNA microarrays, answer the following questions:
A. What is attached to the slide? Be specific about the number of spots, the lengths of DNA fragments, and the origin of the DNA fragments.
B. What is hybridized to the microarray?
C. How is hybridization detected?