ANSWERS TO REVIEW QUESTIONS
CHAPTER 1
1. Gene pool, genome, chromosome, gene, DNA
2. a. An autosome does not carry genes that determine sex. A sex chromosome does.
b. Genotype is the allele constitution in an individual for a particular gene.
Phenotype is the physical expression of an allele combination.
c. DNA is a double-stranded nucleic acid that includes deoxyribose and the
nitrogenous bases adenine, guanine, cytosine and thymine. DNA carries the
genetic information. RNA is a single-stranded nucleic acid that includes ribose
and the nitrogenous bases adenine, guanine, cytosine and uracil. RNA carries
out gene expression.
d. A recessive allele determines phenotype in two copies. A dominant allele
determines phenotype in one copy.
e. A pedigree is a chart of family relationships and traits. A karyotype is a chart of
chromosomes.
f. A gene is a sequence of DNA that encodes a protein. A genome is a complete
copy of the total genetic information for an individual.
3. The sequence of DNA nucleotides (A, G, C, T) in a gene comprises a genetic code
that is read three nucleotides at a time to direct the building of proteins from amino
acids.
4. Humans may have the same genes but differ genetically in the alleles (gene
variants) that they have.
5. A genome-wide association study examines the whole genome for variations such as
SNPs that can be associated with (are found much more often among individuals
with) certain conditions or traits of interest. Gene expression profiling measures
patterns and levels of mRNA to reveal cellular activity. DNA sequencing analyzes the
order of DNA nucleotides (A, G, C, T) in a molecule of DNA or across the entire
genome.
6. Differential expression of genes creates distinctive cell types
7. Gene expressing profiling can be used to identify a drug to which a person’s cancer
cells are likely to respond.
8. GINA protects people from being fired or denied health insurance based on genetic
testing, for companies or organizations above a certain size. Limitations include
extent and type of coverage (no life insurance) and specific sanctions for violations.
9. A diseasome might show that drugs effective for one disease might be useful in
treating another disease, to which it is linked by gene expression patterns.
10. Answers vary depending on student experience. “He has the gene for sense of
humor,” or “She has the gene for a great sense of style.”
11. The genome of a bacterial species that lives in the human gut.
ANSWERS TO APPLIED QUESTIONS
1
1. Students may be concerned about specific diseases in their families, common
conditions such as Alzheimer disease and cardiovascular disease, or in genetic
diseases that they carry and might pass to children.
2. The rate of metabolism of nutrients is multifactorial and represents the interaction of a
number of genes and environmental factors such as variations in the bacterial flora of
the gut.
3. The greater range of complex carbohydrates in the vegetarian diet supports a more
diverse microbiome.
4. A single-gene test.
5. The study on gout is a genome-wide association study. The investigation into muscle
pain and statins is a gene expression study.
6. The insurer is correct, because GINA does not presently cover life insurance.
7. a. health care consumers will not be denied health insurance based on the results of
genetic testing.
b. employers will benefit by clarification and extension of existing employment laws.
There is also the potential for lower health care costs if individuals no longer fear genetic
discrimination and are screened for inherited risks. They can then modify their behavior
to reduce their risk of developing symptoms.
c. insurers benefit by standardization of protocols and a potential lowering of health care
costs if individuals learn their inherited risks and modify their behavior to reduce their risk
of developing symptoms.
d. researchers will have a greater pool of possible participants in clinical trials if people
no longer fear they will be the subject of genetic discrimination.
8. Gene expression profiling.
9. Benefits of the government keeping records of DNA sequences are easing searches
for missing persons, and identifying suspects in a crime. A risk is the danger of
misidentification because people can have DNA sequences in common.
10. Students interested in weight would be interested in the gut microbiome. A student
with acne, skin cancer, or who is prone to sunburn might be interested in the skin
microbiome.
ANSWERS TO WEB ACTIVITIES
1. Many answers are possible. For example, a student might select tests for Parkinson
disease, psoriasis, and hereditary hemochromatosis from 23andMe, but not restless legs
syndrome because it isn’t as serious as the others.
2. Answers vary depending on website visited. An example is the Canadian Barcode of
Life Network whose goal is to identify species in Canada based on mitochondrial DNA
sequences.
2
3. The Human Microbiome Project considers bacteria in or on five sites of the body:
nasal, oral, skin, gastrointestinal, and urogenital.
4. Example: South Africa’s health biotechnology initiative
5. A parent would want to know exactly which traits and conditions would be tested for,
whether testing would be done in the future, if they would be told the results, and how
results would be kept anonymous.
6. Lifestyle factors are important because they are controllable and familiar.
ANSWERS TO FORENSICS FOCUS QUESTIONS
1. In an episode of Law and Order: Special Victims Unit from November 18, 2008, the
remains of an exotic bird in a murder victim’s purse leads to DNA evidence that a tiger
killed her, leading investigators to a man who keeps exotic animals in his New York City
apartment.
2. a. Dr. House invaded privacy because he took DNA from a body, but maybe not
because the person was dead.
b. DNA testing can reveal an inherited disease (human DNA) or an infectious disease
(pathogen DNA).
3