Question 1

Which method is least useful for assessing levels of genetic variation in populations?

Accepted Answer

A)  Phenotypic observation 
B)  DNA sequencing 
C)  VNTRs 
D)  Protein electrophoresis 
E)  RFLP analysis 
A)  Phenotypic observation 
B)  DNA sequencing 
C)  VNTRs 
D)  Protein electrophoresis 
E)  RFLP analysis A

Question 2

Heterozygotes for the sickle-cell allele show higher fitness than either homozygote genotype in malarial regions. This is an example of

Accepted Answer

A)  heterosis. 
B)  codominance. 
C)  founder effect. 
D)  epistasis. 
E)  pleiotropy. 
A)  heterosis. 
B)  codominance. 
C)  founder effect. 
D)  epistasis. 
E)  pleiotropy. A

Question 3

This chapter discussed speciation by genetic divergence following geographic isolation, which is expected to lead to reduced gene flow. This is known as allopatric speciation. A more controversial form of speciation is genetic divergence of populations without physical isolation; this is called sympatric speciation. Can you envision a mechanism or process that would permit two coexisting populations of the same species to begin to diverge without being isolated from one another?

Accepted Answer

Sympatric speciation is thought to be uncommon but almost certainly has occurred. In one general scenario, a form of isolation "in place," or in sympatry, may occur if males or females begin (by drift, perhaps) to prefer different resources-say, a special site for mating or laying eggs. If their mates follow in this "imprinting" process, the two preference populations may begin to experience reduced gene flow between them, which if maintained long enough may bring about a degree of genetic divergence that would be selectively reinforced should some of the individuals from the two populations ever hybridize.

Question 4

Show algebraically that under Hardy-Weinberg equilibrium, allele frequencies will not change from one generation to another.

Accepted Answer

The demonstration is simple. Following a

Question 5

Which of the following populations would be expected to experience the greatest degree of genetic drift?

Accepted Answer

A)  Oak trees in the Great Smoky Mountains National Park 
B)  White-tailed deer in the eastern U.S. 
C)  Wild pandas 
D)  Rat populations in New York City 
E)  Canada geese 
A)  Oak trees in the Great Smoky Mountains National Park 
B)  White-tailed deer in the eastern U.S. 
C)  Wild pandas 
D)  Rat populations in New York City 
E)  Canada geese

Question 6

In the early twentieth century, evolutionary biologists argued whether there was enough genetic variation in populations to explain the diversity of life by natural selection. With the advent of protein electrophoresis and DNA-level analysis, the problem turned on its head: the neutralist school arose from the idea that there was too much genetic variation to be maintained by natural selection. What are some of the arguments and observations neutralists cited to support the idea that much variation is neither favored nor disfavored by natural selection?

Accepted Answer

More genetic variation is expected in no

Question 7

The frequency of a recessive X-linked allele is equal to the phenotypic frequency of males exhibiting that allele.

Accepted Answer

A) True 
 B)False

Question 8

The deciduous forest of eastern North America experienced dramatic changes over the past two to three centuries, transitioning from a nearly continuous forested area to increasingly patchy forest broken up by farming and development. Some species are more sensitive to severe habitat fragmentation than others; what are some characteristics that might make a species more susceptible to the effects of habitat and population fragmentation?

Accepted Answer

Habitat fragmentation leads to "islands"

Question 9

Observed genotypic frequencies in populations rarely match HW expectations exactly. Why is this so, and how can you determine if the frequencies you observe depart from HW in a biologically meaningful degree?

Accepted Answer

There will always be chance deviations i

Question 10

The northern elephant seal, Mirounga angustirostris, suffered a significant population bottleneck in the late nineteenth century, when hunting reduced their population size to as few as 20 individuals. It has since rebounded to several tens of thousands. The related southern elephant seal, M. leonine, was not hunted as intensively. What prediction can you make about the relative levels of heterozygosity in populations of these two species?

Accepted Answer

Much genetic variation would have been l

Question 11

Survival is the single most important process in evolution by natural selection.

Accepted Answer

A) True 
 B)False

Question 12

What is the frequency of the a allele in the beetle population described in question 14?

Accepted Answer

A)  0.91 
B)  0.55 
C)  0.86 
D)  0.09 
E)  0.45 
A)  0.91 
B)  0.55 
C)  0.86 
D)  0.09 
E)  0.45

Question 13

Mutation may be the ultimate source of genetic variation, but sexual reproduction and similar processes like bacterial conjugation or transformation are also important in continually generating novel genetic combinations.

Accepted Answer

A) True 
 B)False

Question 14

If the genotypic frequencies for an allele in an HW population are 0.635 homozygous dominants, 0.430 heterozygotes, and 0.125 homozygous recessives, what is the frequency of the recessive allele?

Accepted Answer

A)  0.65 
B)  0.01 
C)  0.125 
D)  0.875 
E)  0.35 
A)  0.65 
B)  0.01 
C)  0.125 
D)  0.875 
E)  0.35

Question 15

________ is the ultimate source of genetic variation in populations.

Accepted Answer

A)  Natural selection 
B)  Gene flow 
C)  Recombination 
D)  Mutation 
E)  Genetic drift 
A)  Natural selection 
B)  Gene flow 
C)  Recombination 
D)  Mutation 
E)  Genetic drift

Question 16

The Hardy-Weinberg relationship cannot be used to compute allele frequencies when one or more alleles are recessive.

Accepted Answer

A) True 
 B)False

Question 17

For which trait is human mating expected to be nonrandom?

Accepted Answer

A)  Skin color 
B)  Isocitrate dehydrogenase enzyme 
C)  Blood type 
D)  Hair color 
E)  Fingerprint loci 
A)  Skin color 
B)  Isocitrate dehydrogenase enzyme 
C)  Blood type 
D)  Hair color 
E)  Fingerprint loci

Question 18

In the Hardy-Weinberg model, the ideal population is

Accepted Answer

A)  free of mutations. 
B)  randomly mating. 
C)  non-migrating. 
D)  very large. 
E)  all of the above. 
A)  free of mutations. 
B)  randomly mating. 
C)  non-migrating. 
D)  very large. 
E)  all of the above.

Question 19

The population mean for a given measured trait is observed to decline over the course of several generations. This is an example of disruptive selection.

Accepted Answer

A) True 
 B)False

Question 20

Two neighboring Caribbean islands harbor iguana populations. One island (island

Accepted Answer

The migrant subpopulation is 100/800, or

Exam 1: Genetics of Bacteria and Bacteriophages

Which method is least useful for assessing levels of genetic variation in populations?

Heterozygotes for the sickle-cell allele show higher fitness than either homozygote genotype in malarial regions. This is an example of

Show algebraically that under Hardy-Weinberg equilibrium, allele frequencies will not change from one generation to another.

Which of the following populations would be expected to experience the greatest degree of genetic drift?

The frequency of a recessive X-linked allele is equal to the phenotypic frequency of males exhibiting that allele.

Observed genotypic frequencies in populations rarely match HW expectations exactly. Why is this so, and how can you determine if the frequencies you observe depart from HW in a biologically meaningful degree?

Survival is the single most important process in evolution by natural selection.

What is the frequency of the a allele in the beetle population described in question 14?

Mutation may be the ultimate source of genetic variation, but sexual reproduction and similar processes like bacterial conjugation or transformation are also important in continually generating novel genetic combinations.

If the genotypic frequencies for an allele in an HW population are 0.635 homozygous dominants, 0.430 heterozygotes, and 0.125 homozygous recessives, what is the frequency of the recessive allele?

________ is the ultimate source of genetic variation in populations.

The Hardy-Weinberg relationship cannot be used to compute allele frequencies when one or more alleles are recessive.

For which trait is human mating expected to be nonrandom?

In the Hardy-Weinberg model, the ideal population is

The population mean for a given measured trait is observed to decline over the course of several generations. This is an example of disruptive selection.

Two neighboring Caribbean islands harbor iguana populations. One island (island

Variations in Chromosome Structure and Number

Advanced Gene Mapping in Eukaryotes

Gene Mapping in Eukaryotes

Quantitative Genetics

Extensions of Mendelian Genetic Principles

Chromosomal Basis of Inheritance

Molecular Evolution

Population Genetics

Non-Mendelian Inheritance

Genetics of Cancer

Genetic Analysis of Development

Regulation of Gene Expression in Eukaryotes

Mendelian Genetics

Regulation of Gene Expression in Bacteria and Bacteriophages

Genomics

Applications of Recombinant DNA Technology

Recombinant DNA Technology

DNA Mutation, DNA Repair, and Transposable Elements

Gene Expression: Translation

Gene Expression: Transcription

Gene Control of Proteins

DNA Replication

DNA: The Genetic Material

Genetics: an Introduction

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