Chapter Nineteen
ANSWERS TO REVIEW QUESTIONS
1. BRCA1, human insulin gene, human growth hormone gene
2. A DNA sequence alone is not patentable because it is a product of nature. DNA as part of a
diagnostic kit, however, is part of a medical device. The parts other than the DNA sequence
are necessary for the device to work, and the device is not a product of nature.
3. a. Restriction enzymes cut DNA at specific sequences. They can be used to create DNA
fragments for constructing recombinant DNA molecules.
b. Cloning vectors carry DNA sequences into cells.
c. DNA microarrays are used to evaluate patterns of gene expression.
d. Various uses such as primers, genetic markers, donor sequences, or to block
expression of mutations.
4. Antibiotics are generally used to set up a system where only cells that have taken up foreign
DNA can survive.
5. Human insulin DNA cut with a restriction enzyme, vector DNA cut with the same restriction
enzyme, E. coli, DNA ligase, selection mechanism (such as antibiotic).
6. Bacteria could not manufacture the products of human genes if the genetic code was not
universal. The wrong amino acids would be incorporated into proteins.
7. A drug obtained using recombinant DNA technology does not contain contaminants found in
proteins extracted from organisms, it is not allergenic, and it is the human version of the
protein.
8. A transgenic animal has human DNA and can therefore be better models of human disease,
but the human gene might not be expressed the same way in a mouse, for example, as a
human, because of differences in development times.
9. Conventional breeding considers phenotypes only, whereas genetic modification alters a
specific and known DNA sequence.
10. Examining the whole exome will reveal new genes associated with the disease and genetic
relationships shared with other diseases.
11. Gene silencing or genome editing can be used to silence an oncogene or other diseasecausing allele, or to counter exon skipping.
ANSWERS TO APPLIED QUESTIONS
1. The gene for the E. coli enzyme is cut with a restriction enzyme, isolated and introduced into
a fertilized pig egg via microinjection or other technique. The embryo is transferred to a
surrogate and develops. Animals with phenotypes indicating they harbor cells with the E.
coli gene are bred to each other to yield homozygous transgenic pigs.
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without the prior written consent of McGraw-Hill Education.
2. Opinion. A gene exists in nature; a cDNA does not.
3. The author thinks that forcing farmers to use GM crops and a particular company’s pesticide
is unethical, but the GM crops themselves are not dangerous, although pollination can
transfer them to places where they are not wanted.
4. (1) A goat produces human EPO in its milk.
(2) A mouse produces jellyfish GFP in its blood plasma.
(3) A chicken produces human clotting factor in its egg whites.
5. Human collagen produced in transgenic mice is less likely to include infectious agents than
collagen obtained from hooves and hides. It is also the human version of the protein, which
is less likely to stimulate an immune response than the cow type.
6. This is a conundrum that has been around for years: how the same biotechnology can elicit
different responses from the public depending on context. For example, a drug to treat
Ebola virus disease is manufactured in transgenic tobacco plants. Are the GM plants evil?
Dangerous? Why is GM corn bad but a drug or vaccine made in a transgenic organism or
using recombinant DNA not?
7. Mice can express human genes because they use the same genetic code.
8. Other genes might be involved that the researcher does not include or know about.
9. Answers vary on crop selected. Bt corn, for example, is safe to eat, can travel, and forces
growers to purchase GM seed.
10. Recombinant DNA technology
11. Taking the hormone suppressed the ability of Armstrong’s body to make EPO. The source
of the EPO wouldn’t matter—the effect on his body would be the same.
ANSWERS TO WEB ACTIVITIES
1. In 2006 Andrew Z. Fire and Craig C. Mello won the 2006 Nobel Prize in Physiology or
Medicine for their work on RNA interference, discovering how RNA molecules silence viral
genes and regulate expression of genes. In 2008 Martin Chalfie, Osamu Shimomura, and
Roger Y. Tsien won the Nobel Prize in Chemistry for developing the jellyfish’s green
fluorescent protein as a marker for any gene in any organism.
2. Humulin® for diabetes, Procrit® used to treat anemia and Actimmune® for infection.
3. Herbicide-resistant soy and corn. Opinion on whether being GMO would matter.
4. http://jaxmice.jax.org/strain/009617.html describes a mouse that is transgenic for the human
gene that is mutant in SCID-X1, a condition described in chapter 20.
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without the prior written consent of McGraw-Hill Education.
5. a. A human growth hormone product called Sero-Vital claims to “Turn Back Time
with the “Anti-Aging” Breakthrough Everyone Is Talking About!”
b. Taking hormones without a health care provider’s care is dangerous.
ANSWERS TO CASE STUDIES AND RESEARCH RESULTS
1. Give a ewe hormones to make her superovulate. Apply ram sperm to ewe’s reproductive
tract. Flush out fertilized ova, and inject them with human AAT gene linked to sheep gene
promoter that will control its expression. Place GM fertilized ova into sheep surrogate
mothers. Select heterozygous offspring, breed them to obtain homozygotes. Milk female
homozygotes and extract human drug.
2. a.
b.
c.
d.
e.
Yellow fluorescence
Red fluorescence
Blank or no signal on chip
Screen before and after samples
Compare normal and sunburnt skin using DNA microarray
3. Reporters need to report the number of people in a clinical trial, how long the trial
proceeded, the endpoints, the nature of the phenotype (severity of disease in participants),
and the control group.
4. a.
b.
c.
d.
a gene expression microarray
can RSV be present without causing symptoms?
gene expression microarray or a microarray with gene variants unique to RSV
stratify infected babies by severity of symptoms and identify differences in gene
expression.
Copyright © 2015 McGraw-Hill Education. All rights reserved. No reproduction or distribution
without the prior written consent of McGraw-Hill Education.