Question 1

The molecular clock has limited usefulness for estimating divergence times among species in part due to the saturation of DNA sequences. This occurs because

Accepted Answer

A)  DNA sequences are unable to revert back to previous allelic states. 
B)  the variation in the substitution rate between closely related lineages prevents accurate estimation of divergence time. 
C)  variation in population sizes among lineages changes the effect of genetic drift. 
D)  in highly diverged lineages, substitutions will occur at sites that have been substituted previously. 
A)  DNA sequences are unable to revert back to previous allelic states. 
B)  the variation in the substitution rate between closely related lineages prevents accurate estimation of divergence time. 
C)  variation in population sizes among lineages changes the effect of genetic drift. 
D)  in highly diverged lineages, substitutions will occur at sites that have been substituted previously.

Question 2

Ka measures the rate of nonsynonymous substitutions. Why is the ratio of Ka /Ks used to test for positive selection rather than just Ka alone?

Accepted Answer

K_s is needed to provide a basel

Question 3

Genetic drift causes changes in

Accepted Answer

A)  the strength of natural selection. 
B)  allele frequencies. 
C)  population size. 
D)  the genetic code. 
A)  the strength of natural selection. 
B)  allele frequencies. 
C)  population size. 
D)  the genetic code.

Question 4

F-statistics can be used to quantify the effects of genetic drift by measuring

Accepted Answer

A)  the change in identity by descent over time. 
B)  effective population size. 
C)  the rate of change in allele frequencies. 
D)  the relative strength of selection on two alleles. 
A)  the change in identity by descent over time. 
B)  effective population size. 
C)  the rate of change in allele frequencies. 
D)  the relative strength of selection on two alleles.

Question 5

In a population of mice there are two alleles for coat color, with the brown allele beneficial over the white allele. Under what conditions would the alleles be effectively neutral if the effective population size is 200?

Accepted Answer

Drift dominates when

Question 6

The figure shows the Ka /Ks values for two regulatory genes in pairs of species in (A) North American tarweeds and (B) Hawaiian silverswords. The dashed lines are the mean Ka/Ks values. What do these data indicate about how these genes are evolving differently in these two groups of taxa? A

B

Accepted Answer

A)  They are evolving neutrally in the tarweeds and under purifying selection in the silverswords. 
B)  There have been more mutations in this gene in the silverswords than the tarweeds. 
C)  They have experienced purifying selection in the tarweeds and positive selection in the silverswords. 
D)  They have undergone gene conversion in the tarweeds but not in the silverswords. 
A)  They are evolving neutrally in the tarweeds and under purifying selection in the silverswords. 
B)  There have been more mutations in this gene in the silverswords than the tarweeds. 
C)  They have experienced purifying selection in the tarweeds and positive selection in the silverswords. 
D)  They have undergone gene conversion in the tarweeds but not in the silverswords.

Question 7

Imagine that, of three species, it is known that species 1 and 3 were separated 10 million years ago, based on geologic measurements. Genetic analysis at a neutral locus indicates that these species differ by 100 substitutions. If there are 10 substitutions separating species 1 and 2, approximately how long ago did these species diverge?

Accepted Answer

A)  0.1 million years ago 
B)  1 million years ago 
C)  10 million years ago 
D)  100 million years ago 
A)  0.1 million years ago 
B)  1 million years ago 
C)  10 million years ago 
D)  100 million years ago

Question 8

Consider a population of 10,000 pigeons founded by a population in which no alleles were identical by descent. After 30 generations in this Wright-Fisher population, what will the expected identity by descent be?

Accepted Answer

F₃₀ = 1 - (1

Question 9

If we trace the genealogies of two gene copies back in time, the point at which they are descended from the same ancestral gene copy is called the

Accepted Answer

A)  coalescent point. 
B)  stable equilibrium. 
C)  genetic drift. 
D)  population divergence point. 
A)  coalescent point. 
B)  stable equilibrium. 
C)  genetic drift. 
D)  population divergence point.

Question 10

The figure shows aligned homologous gene sequences from two species. What is the dominant evolutionary force acting on this gene in these species?

Accepted Answer

A)  positive selection 
B)  recombination 
C)  genetic drift 
D)  purifying selection 
A)  positive selection 
B)  recombination 
C)  genetic drift 
D)  purifying selection

The molecular clock has limited usefulness for estimating divergence times among species in part due to the saturation of DNA sequences. This occurs because

K_a measures the rate of nonsynonymous substitutions. Why is the ratio of K_a/K_s used to test for positive selection rather than just K_a alone?

Genetic drift causes changes in

F-statistics can be used to quantify the effects of genetic drift by measuring

In a population of mice there are two alleles for coat color, with the brown allele beneficial over the white allele. Under what conditions would the alleles be effectively neutral if the effective population size is 200?

The figure shows the K_a/K_s values for two regulatory genes in pairs of species in (A) North American tarweeds and (B) Hawaiian silverswords. The dashed lines are the mean K_a/K_s values. What do these data indicate about how these genes are evolving differently in these two groups of taxa? A B

Consider a population of 10,000 pigeons founded by a population in which no alleles were identical by descent. After 30 generations in this Wright-Fisher population, what will the expected identity by descent be?

If we trace the genealogies of two gene copies back in time, the point at which they are descended from the same ancestral gene copy is called the

The figure shows aligned homologous gene sequences from two species. What is the dominant evolutionary force acting on this gene in these species?

An Overview of Evolutionary Biology

Early Evolutionary Ideas and Darwin S Insight

Natural Selection

Phylogeny and Evolutionary History

Inferring Phylogeny

Transmission Genetics and the Sources of Genetic Variation

The Genetics of Populations

Evolution at Multiple Loci

Genome Evolution

The Origin and Evolution of Early Life

Major Transitions

Evolution and Development

Species and Speciation

Extinction and Evolutionary Trends

The Evolution of Sex

The Evolution of Sociality

Coevolution

Human Evolution

Evolution and Medicine

Filters

Exam 8: Evolution in Finite Populations

The molecular clock has limited usefulness for estimating divergence times among species in part due to the saturation of DNA sequences. This occurs because

Ka measures the rate of nonsynonymous substitutions. Why is the ratio of Ka /Ks used to test for positive selection rather than just Ka alone?

Genetic drift causes changes in

F-statistics can be used to quantify the effects of genetic drift by measuring

In a population of mice there are two alleles for coat color, with the brown allele beneficial over the white allele. Under what conditions would the alleles be effectively neutral if the effective population size is 200?

The figure shows the Ka /Ks values for two regulatory genes in pairs of species in (A) North American tarweeds and (B) Hawaiian silverswords. The dashed lines are the mean Ka/Ks values. What do these data indicate about how these genes are evolving differently in these two groups of taxa? A B

Consider a population of 10,000 pigeons founded by a population in which no alleles were identical by descent. After 30 generations in this Wright-Fisher population, what will the expected identity by descent be?

If we trace the genealogies of two gene copies back in time, the point at which they are descended from the same ancestral gene copy is called the

The figure shows aligned homologous gene sequences from two species. What is the dominant evolutionary force acting on this gene in these species?

An Overview of Evolutionary Biology

Early Evolutionary Ideas and Darwin S Insight

Natural Selection

Phylogeny and Evolutionary History

Inferring Phylogeny

Transmission Genetics and the Sources of Genetic Variation

The Genetics of Populations

Evolution at Multiple Loci

Genome Evolution

The Origin and Evolution of Early Life

Major Transitions

Evolution and Development

Species and Speciation

Extinction and Evolutionary Trends

The Evolution of Sex

The Evolution of Sociality

Coevolution

Human Evolution

Evolution and Medicine

Filters

K_a measures the rate of nonsynonymous substitutions. Why is the ratio of K_a/K_s used to test for positive selection rather than just K_a alone?

The figure shows the K_a/K_s values for two regulatory genes in pairs of species in (A) North American tarweeds and (B) Hawaiian silverswords. The dashed lines are the mean K_a/K_s values. What do these data indicate about how these genes are evolving differently in these two groups of taxa? A B