Human Genetics: Concepts and Applications (Lewis), 9th Edition

Chapter 15: Changing Allele Frequencies

Practice Tests

1
Worldwide, about 1/3 of all marriages occur between people who were born fewer than ten miles apart. This is an example of _____.
A)natural selection
B)genetic drift
C)nonrandom mating
D)migration
2
Albinism is uncommon in the United States but affects 1/200 Hopi Indians. A contributing factor for this high increase is _____.
A)nonrandom mating
B)migration
C)genetic drift
D)natural selection
3
True or False. Consanguinity increases the proportion of heterozygotes in the population.
A)True
B)False
4
Endogamy refers to _____.
A)marriage within a community
B)marriage to a brother or sister
C)marriage to a cousin
D)marriage to a person from another country
5
Different allele frequencies from one geographic area to an adjacent area constitute _____.
A)founder effects
B)bottlenecks
C)clines
D)balanced polymorphisms
6
Assume that "school spirit" is a genetically controlled trait. At your university, the dominant allele for "we are #1!" occurs at a frequency of 1.0. At your rival university, the frequency of this allele is 0.3. In an effort to obtain additional funding for your university, you attempt to increase the frequency of the #1 allele at the rival institution by sending your graduates there to live and raise families. This would be an example of _____.
A)nonrandom mating
B)migration
C)genetic drift
D)natural selection
7
True or False. One of the conditions that must be met for Hardy-Weinberg equilibrium is that organisms must be free to move from population to population.
A)True
B)False
8
If a small number of individuals are isolated from the larger population and mate only among themselves, allele frequencies may change as a result of _____.
A)nonrandom mating
B)migration
C)genetic drift
D)natural selection
9
A classic example of ____ is the Dunker community of Germantown, Pennsylvania.
A)a population bottleneck
B)geographical isolation
C)a founder effect
D)natural selection
10
A ____ occurs when many members of a group die and only a few are left, by chance, to replenish the numbers.
A)population bottleneck
B)geographical isolation
C)founder effect
D)natural selection
11
True or False. Genetic drift is a random process.
A)True
B)False
12
Genetic disorders such as Tay-Sachs and Gaucher disease are more common in Ashkenazi Jewish population because _____.
A)they are a more highly variable group
B)mutations occur at a higher rate in this group
C)their history includes several population bottlenecks
D)selection, mutation, and migration have not occurred
13
Although the present day cheetah populations appear to be the result of two extreme population bottlenecks, the populations seem to be in good shape because _____.
A)there are so many individuals alive today
B)most of the cheetahs are healthy
C)there is migration among the many different populations
D)of the genetic diversity within the populations
14
Founder effect and population bottlenecks are both examples of _____.
A)inbreeding
B)migration
C)nonrandom mating
D)genetic drift
15
Which of the following communities of humans is not an example of a founder effect?
A)Dunkers of Pennsylvania
B)Old Order Amish of Pennsylvania
C)Mennonites of Pennsylvania
D)French Canadians of Quebec
E)All of the above
16
For Hardy-Weinberg equilibrium to be maintained, mutation must be _____.
A)occurring at a very low rate
B)occurring in some individuals but not others
C)absent
D)Mutation does not affect Hardy-Weinberg equilibrium.
17
The collection of deleterious alleles in populations is called _____.
A)genetic drift
B)selection
C)genetic load
D)migration
18
True or False. A change in the DNA sequence that does not substitute an amino acid does not change the protein, and therefore has no effect on the phenotype. Such a change therefore cannot be subject to natural selection.
A)True
B)False
19
True or False. Some mutations can increase an individual's chance of survival.
A)True
B)False
20
Which factor has the least influence on disrupting Hardy-Weinberg equilibrium?
A)nonrandom mating
B)migration
C)mutation
D)genetic drift
21
True or False. Natural selection results in differential survival based on phenotype.
A)True
B)False
22
Sickle cell disease illustrates a balanced polymorphism because carriers are resistant to _____.
A)malaria
B)kuru
C)tuberculosis
D)diarrheal disease
23
Considering your response to the above question, which of the following genotypic classes is susceptible to malaria?
A)heterozygous normal males
B)G6PD normal males
C)homozygous normal males
D)b and c
24
Deleterious alleles can be maintained in a population when heterozygotes have a reproductive advantage. This situation is described as _____.
A)inbreeding
B)geographical isolation
C)a population bottleneck
D)a balanced polymorphism
25
The study of tuberculosis demonstrates the effects of _____.
A)inbreeding
B)geographical isolation
C)a population bottleneck
D)natural selection
26
Full-blown AIDS represents the ____ stage of an HIV infection.
A)first
B)second
C)third
D)fourth
27
True or False. Frequencies of different mutations in different populations provide information on the natural history of alleles.
A)True
B)False
28
True or False. Mutational analysis in various populations indicates that PKU originated only once.
A)True
B)False
29
When a group of people is subservient to another, genes tend to "flow" from one group to the other as the males of the ruling class have children with females of the underclass, often forcibly. This best describes _____.
A)random mating
B)cline
C)nonrandom mating
D)genetic drift
30
True or False. If a population travels (migrates) and picks up new individuals, allele (and genotype) frequencies can change.
A)True
B)False
31
Consanguinity and endogamy increase the proportion of ____ in a population.
A)heterozygotes
B)homozygotes
C)hemizygotes
D)species
32
Smith-Lemli-Opitz syndrome provides patients with protection against _____.
A)malaria
B)fungal infection in fetuses
C)diarrheal disease
D)cardiovascular disease
33
Forces that change allele frequencies include _____.
A)nonrandom mating
B)migration
C)genetic drift
D)mutation
E)natural selection
F)All of the above affect allele frequencies.
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