Question 1

Which of the following statements about linkage disequilibrium is false?

Accepted Answer

A)  Physical linkage is required for two loci to be in a state of linkage disequilibrium. 
B)  Linkage disequilibrium is a statistical state detected when two loci segregate independently. 
C)  Linkage disequilibrium is a transient state that can disappear with genetic recombination. 
D)  A new mutation first exists in a state of perfect, chromosome-wide linkage disequilibrium. 
A)  Physical linkage is required for two loci to be in a state of linkage disequilibrium. 
B)  Linkage disequilibrium is a statistical state detected when two loci segregate independently. 
C)  Linkage disequilibrium is a transient state that can disappear with genetic recombination. 
D)  A new mutation first exists in a state of perfect, chromosome-wide linkage disequilibrium. A

Question 2

The graph below plots survival versus birth weight for human babies. What type of selection is operating?

Accepted Answer

A)  stabilizing 
B)  disruptive 
C)  directional 
D)  negative frequency-dependent 
A)  stabilizing 
B)  disruptive 
C)  directional 
D)  negative frequency-dependent A

Question 3

What effect does each type of selection, directional, stabilizing, and disruptive, have on the mean and variance of the trait in the next generation?

Accepted Answer

Directional selection tends to shift the mean of the trait in one direction, either increasing or decreasing it, depending on the selective pressure. This results in a change in the mean of the trait in the next generation. Stabilizing selection, on the other hand, reduces the variance of the trait by favoring individuals with traits closer to the mean, leading to a decrease in variance in the next generation. Disruptive selection, however, increases the variance of the trait by favoring individuals with extreme traits, leading to an increase in variance in the next generation. Overall, each type of selection has a different effect on the mean and variance of the trait in the next generation, with directional selection shifting the mean, stabilizing selection reducing variance, and disruptive selection increasing variance.

Question 4

If A1 represents an allele at one locus and B1 represents an allele at another locus, what is $P _ { A _ { 1 } } * P _ { B _ { 1 } }$ ?

Accepted Answer

A)  the expected frequency of A1B1 individuals if the two loci are segregating independently 
B)  the observed frequency of individuals with A1 and B1 
C)  all possible combinations of the A and B alleles 
D)  the frequency of A1 and B1 in the population 
A)  the expected frequency of A1B1 individuals if the two loci are segregating independently 
B)  the observed frequency of individuals with A1 and B1 
C)  all possible combinations of the A and B alleles 
D)  the frequency of A1 and B1 in the population

Question 5

Which of the following is true of QTL association studies?

Accepted Answer

A)  They pinpoint the specific gene(s) responsible for phenotypic variation. 
B)  F1 offspring are examined to look for genetic markers linked to phenotypic variation. 
C)  They rely on recombination to create a wide range of phenotypic variation. 
D)  all of the above 
E)  none of the above 
A)  They pinpoint the specific gene(s) responsible for phenotypic variation. 
B)  F1 offspring are examined to look for genetic markers linked to phenotypic variation. 
C)  They rely on recombination to create a wide range of phenotypic variation. 
D)  all of the above 
E)  none of the above

Question 6

How does genome wide association (GWA) mapping differ from quantitative trait locus (QTL) mapping?

Accepted Answer

A)  GWA mapping samples individuals from within a single population. 
B)  GWA mapping crosses individuals from genetically divergent populations. 
C)  QTL mapping searches for markers associated with expression of a trait. 
D)  GWA mapping can identify the specific gene in that causes a trait. 
A)  GWA mapping samples individuals from within a single population. 
B)  GWA mapping crosses individuals from genetically divergent populations. 
C)  QTL mapping searches for markers associated with expression of a trait. 
D)  GWA mapping can identify the specific gene in that causes a trait.

Question 7

Please describe a scenario where selection occurs on a trait, but there is no evolutionary change.

Accepted Answer

One scenario where selection occurs on a

Question 8

Broad sense heritability differs from narrow sense heritability in that

Accepted Answer

A)  for broad sense heritability, VG includes only additive effects of alleles. 
B)  for broad sense heritability, VG includes additive, dominance, and epistatic effects. 
C)  broad sense heritability includes only components of variance that cause offspring to resemble their parents. 
D)  all of the above 
E)  none of the above 
A)  for broad sense heritability, VG includes only additive effects of alleles. 
B)  for broad sense heritability, VG includes additive, dominance, and epistatic effects. 
C)  broad sense heritability includes only components of variance that cause offspring to resemble their parents. 
D)  all of the above 
E)  none of the above

Question 9

Consider selection on a quantitative trait such as height. Please graph a fitness function (fitness on the y axis; height on the x axis) for each of the following types of selection: directional, stabilizing, and disruptive.

Accepted Answer

To graph fitness functions for each type

Question 10

A trait with h2 = 0

Accepted Answer

A)  must have no genetic basis. 
B)  means that most of the phenotypic variation in the population is explained by differences in the alleles that individuals have. 
C)  means that there is no phenotypic variation. 
D)  means that the phenotypic variation in the population is explained by differences in the environments experienced by individuals. 
E)  a and d 
A)  must have no genetic basis. 
B)  means that most of the phenotypic variation in the population is explained by differences in the alleles that individuals have. 
C)  means that there is no phenotypic variation. 
D)  means that the phenotypic variation in the population is explained by differences in the environments experienced by individuals. 
E)  a and d

Question 11

Which event would result in an allele or alleles being in a state of perfect linkage disequilibrium?

Accepted Answer

A)  A new mutation arises on a chromosome. 
B)  Two individuals from a different species mate to produce a hybrid offspring. 
C)  Crossing over of chromosomes occurs during meiosis. 
D)  a and b 
E)  a, b, and c 
A)  A new mutation arises on a chromosome. 
B)  Two individuals from a different species mate to produce a hybrid offspring. 
C)  Crossing over of chromosomes occurs during meiosis. 
D)  a and b 
E)  a, b, and c

Question 12

Which of the following steps is a part of QTL association studies?

Accepted Answer

A)  crossing individuals from genetically divergent populations 
B)  sampling a large number of individuals from within a population 
C)  raising individuals in a large range of environmental conditions 
D)  calculating the expected frequency of alleles in a population 
A)  crossing individuals from genetically divergent populations 
B)  sampling a large number of individuals from within a population 
C)  raising individuals in a large range of environmental conditions 
D)  calculating the expected frequency of alleles in a population

Question 13

A quantitative trait locus is

Accepted Answer

A)  a section of DNA that regulates the expression of a gene. 
B)  a genetic mutation responsible for a certain disease. 
C)  a change in the phenotype produced by a single genotype. 
D)  a stretch of DNA correlated with variation in a phenotypic trait. 
A)  a section of DNA that regulates the expression of a gene. 
B)  a genetic mutation responsible for a certain disease. 
C)  a change in the phenotype produced by a single genotype. 
D)  a stretch of DNA correlated with variation in a phenotypic trait.

Question 14

Which of the following equations illustrates phenotypic variation that comes from both the genotype and the environment?

Accepted Answer

A)  VP = VG 
B)  VP = VE 
C)  VP = VG + VE 
D)  VP = VG + VE + VG×E 
A)  VP = VG 
B)  VP = VE 
C)  VP = VG + VE 
D)  VP = VG + VE + VG×E

Question 15

Below are some different scenarios for the heritability of a trait and the selection differential in a population. Which scenario will produce the largest response to selection?

Accepted Answer

A)  h2 = 0.9; S = 0.6 
B)  h2 = 0.5; S = 0.9 
C)  h2 = 0.2; S = 0.1 
D)  h2 = 0.5; S = 0.5 
A)  h2 = 0.9; S = 0.6 
B)  h2 = 0.5; S = 0.9 
C)  h2 = 0.2; S = 0.1 
D)  h2 = 0.5; S = 0.5

Question 16

If chromosomes were passed down unchanged from generation to generation, then this state would best be described as

Accepted Answer

A)  linkage equilibrium. 
B)  linkage disequilibrium. 
C)  broad sense heritability. 
D)  physical linkage. 
A)  linkage equilibrium. 
B)  linkage disequilibrium. 
C)  broad sense heritability. 
D)  physical linkage.

Question 17

You are studying directional selection on neck length in two giraffe populations. Below you can see data on neck length (in inches) of the whole population and breeding parents for each of the two populations. $$\begin{array} { | c | c | c | c | } 
\hline \begin{array} { c } 
\text { Neck length of individuals } \
\text { in population 1 }
\end{array} & \begin{array} { c } 
\text { Neck length of breeders } \
\text { in population 1 }
\end{array} & \begin{array} { c } 
\text { Neck length of } \
\text { individuals in } \
\text { population 2 }
\end{array} & \begin{array} { c } 
\text { Neck length of } \
\text { breeders in } \
\text { population 2 }
\end{array} \
\hline 50 & 90 & 55 & 90 \
\hline 80 & 80 & 75 & 60 \
\hline 90 & 75 & 45 & 70 \
\hline 45 & 95 & 60 & 75 \
\hline 60 & 60 & 40 & 80\
\hline 35 & & 90 & \
\hline 95 & & 45 & \
\hline 40 & & 70 & \
\hline 75 & & 80 & \
\hline
\end{array}$$ (a) Calculate the selection differential for each population. Show your work.
You also have data on the length of necks for parents and their offspring (offspring corresponding to each midparent listed in the adjacent cell). $$\begin{array} { | l | l | l | l | } 
\hline \text { Midparent pop 1 } & \text { Midoffspring pop 1 } & \text { Midparent pop 2 } & \text { Midoffspring pop 2 } \
\hline 85 & 84 & 80 & 65 \
\hline 90 & 88 & 75 & 90 \
\hline 75 & 75 & 85 & 55 \
\hline 65 & 62 & 65 & 75 \
\hline 70 & 69 & 70 & 85 \
\hline 80 & 82 & 95 & 75 \
\hline 95 & 94 & 60 & 80 \
\hline
\end{array}$$ (b) Describe how you would use this data to calculate narrow sense heritability.
(c) Based on parts a and b, in which population would you expect to see the largest evolutionary change in neck length in the next generation? Explain your answer.

Accepted Answer

(a) To calculate the selection different

Question 18

Given the graph below, and assuming that corolla flare is heritable, what type of selection should occur?

Accepted Answer

A)  directional 
B)  stabilizing 
C)  disruptive 
D)  overdominance 
E)  frequency-dependent 
A)  directional 
B)  stabilizing 
C)  disruptive 
D)  overdominance 
E)  frequency-dependent

Question 19

When sources of genetic variation act independently, their effects are

Accepted Answer

A)  additive. 
B)  dominant. 
C)  non-additive. 
D)  recessive. 
A)  additive. 
B)  dominant. 
C)  non-additive. 
D)  recessive.

Question 20

Which response to different environmental conditions would you expect from a species that has a high VG×E for a trait?

Accepted Answer

A)  All genotypes respond similarly to environmental conditions. 
B)  The magnitude of each genotype's response is always similar. 
C)  Different genotypes have varying responses to different conditions. 
D)  The same genotype will have the same response to different conditions. 
A)  All genotypes respond similarly to environmental conditions. 
B)  The magnitude of each genotype's response is always similar. 
C)  Different genotypes have varying responses to different conditions. 
D)  The same genotype will have the same response to different conditions.

Which of the following statements about linkage disequilibrium is false?

The graph below plots survival versus birth weight for human babies. What type of selection is operating?

What effect does each type of selection, directional, stabilizing, and disruptive, have on the mean and variance of the trait in the next generation?

If A₁ represents an allele at one locus and B₁ represents an allele at another locus, what is $P _ { A _ { 1 } } * P _ { B _ { 1 } }$ ?

Which of the following is true of QTL association studies?

How does genome wide association (GWA) mapping differ from quantitative trait locus (QTL) mapping?

Please describe a scenario where selection occurs on a trait, but there is no evolutionary change.

Broad sense heritability differs from narrow sense heritability in that

Consider selection on a quantitative trait such as height. Please graph a fitness function (fitness on the y axis; height on the x axis) for each of the following types of selection: directional, stabilizing, and disruptive.

A trait with h² = 0

Which event would result in an allele or alleles being in a state of perfect linkage disequilibrium?

Which of the following steps is a part of QTL association studies?

A quantitative trait locus is

Which of the following equations illustrates phenotypic variation that comes from both the genotype and the environment?

Below are some different scenarios for the heritability of a trait and the selection differential in a population. Which scenario will produce the largest response to selection?

If chromosomes were passed down unchanged from generation to generation, then this state would best be described as

Given the graph below, and assuming that corolla flare is heritable, what type of selection should occur?

When sources of genetic variation act independently, their effects are

Which response to different environmental conditions would you expect from a species that has a high V_G×E for a trait?

The Whale and the Virus: How Scientists Study Evolution

From Natural Philosophy to Darwin: a Brief History of Evolutionary Ideas

What the Rocks Say: How Geology and Paleontology Reveal the History of Life

The Tree of Life: How Biologists Use Phylogeny to Reconstruct the Deep Past

Raw Material: Heritable Variation Among Individuals

The Ways of Change: Drift and Selection

The History in Our Genes

From Genes to Traits: the Evolution of Genetic Networks and Development

Natural Selection: Empirical Studies in the Wild

Sex: Causes and Consequences

After Conception: the Evolution of Life History and Parental Care

The Origin of Species

Macroevolution: the Long Run

Intimate Partnerships: How Species Adapt to Each Other

Brains and Behavior

Human Evolution: a New Kind of Ape

Evolutionary Medicine

Filters

Exam 7: Beyond Alleles: Quantitative Genetics and the Evolution of Phenotypes

Which of the following statements about linkage disequilibrium is false?

The graph below plots survival versus birth weight for human babies. What type of selection is operating?

What effect does each type of selection, directional, stabilizing, and disruptive, have on the mean and variance of the trait in the next generation?

If A1 represents an allele at one locus and B1 represents an allele at another locus, what is PA1∗PB1P _ { A _ { 1 } } * P _ { B _ { 1 } }PA1​​∗PB1​​ ?

Which of the following is true of QTL association studies?

How does genome wide association (GWA) mapping differ from quantitative trait locus (QTL) mapping?

Please describe a scenario where selection occurs on a trait, but there is no evolutionary change.

Broad sense heritability differs from narrow sense heritability in that

Consider selection on a quantitative trait such as height. Please graph a fitness function (fitness on the y axis; height on the x axis) for each of the following types of selection: directional, stabilizing, and disruptive.

A trait with h2 = 0

Which event would result in an allele or alleles being in a state of perfect linkage disequilibrium?

Which of the following steps is a part of QTL association studies?

A quantitative trait locus is

Which of the following equations illustrates phenotypic variation that comes from both the genotype and the environment?

Below are some different scenarios for the heritability of a trait and the selection differential in a population. Which scenario will produce the largest response to selection?

If chromosomes were passed down unchanged from generation to generation, then this state would best be described as

Given the graph below, and assuming that corolla flare is heritable, what type of selection should occur?

When sources of genetic variation act independently, their effects are

Which response to different environmental conditions would you expect from a species that has a high VG×E for a trait?

The Whale and the Virus: How Scientists Study Evolution

From Natural Philosophy to Darwin: a Brief History of Evolutionary Ideas

What the Rocks Say: How Geology and Paleontology Reveal the History of Life

The Tree of Life: How Biologists Use Phylogeny to Reconstruct the Deep Past

Raw Material: Heritable Variation Among Individuals

The Ways of Change: Drift and Selection

The History in Our Genes

From Genes to Traits: the Evolution of Genetic Networks and Development

Natural Selection: Empirical Studies in the Wild

Sex: Causes and Consequences

After Conception: the Evolution of Life History and Parental Care

The Origin of Species

Macroevolution: the Long Run

Intimate Partnerships: How Species Adapt to Each Other

Brains and Behavior

Human Evolution: a New Kind of Ape

Evolutionary Medicine

Filters

If A₁ represents an allele at one locus and B₁ represents an allele at another locus, what is $P _ { A _ { 1 } } * P _ { B _ { 1 } }$ ?

A trait with h² = 0

Which response to different environmental conditions would you expect from a species that has a high V_G×E for a trait?