Deck 7: The Genetics of Populations

Question 1

If we follow a population through time and observe that allele frequencies change or genotypic frequencies change in this population,this may be because

A)the population size is small.
C)mating is non-random.
B)selection is operating on the locus.
D)Any of the above

Answer 1

D

Question 2

Which type of equilibrium is modeled in the following figure?

A)Stable
B)Unstable
C)Mixed
D)Neutral
E)Complex

Answer 2

C

Question 3

Hardy and Punnett were two of the founders of which biological field of study?

A)Quantitative genetics
B)Qualitative genetics
C)Population genetics
D)Molecular genetics
E)None of the above

Answer 3

C

Question 4

The figure below demonstrates that

A)frequency dependent selection results in a stable polymorphism.
B)the frequency of the A₁ allele (p) will always go to fixation.
C)the frequency of the A₁ allele (p) will always go to zero.
D)the frequency of the A₁ allele (p) may go to one or zero depending on the initial value of p.
E)frequency selection leads to the random loss of alleles.

Question 5

Many early evolutionary biologists rejected Mendel's ideas because

A)they were not interested in peas.
B)Punnett's conclusions contradicted Mendel's.
C)heterozygote crosses yield a 2:2 ratio of genotypes.
D)Hardy's conclusions contradicted Mendel's.
E)None of the above

Question 6

When considering the following figure,the top panel refers to _________ and the bottom panel refers to _________.

A)population-level thinking; individual-level thinking
B)individual-level thinking; population-level thinking
C)Yule-thinking; Mendel-thinking
D)evolutionary thinking; ecological thinking
E)geographic thinking; spatial thinking

Question 7

Consider a biallelic locus with alleles A₁ and A₂.A₁ mutates to A₂ with a forward mutation rate of 0.0000025.A₂ mutates back to A₁ with a reverse mutation rate of 0.0000010.What will be the equilibrium frequency of the A₁ allele?

A)0.0407
B)0.1298
C)0.1820
D)0.2857
E)0.3869

Question 8

The figure above depicts the change in p over time when the forward mutation rate is twice the reverse mutation rate.This results in a p equilibrium frequency that approaches 0.333.If the forward mutation rate was four times as fast as the reverse mutation rate,one would expect the equilibrium value of p to be

A)stable.
B)unstable.
C)lower than 0.33.
D)higher than 0.33.
E)A and C

Question 9

Which assumption of the Hardy-Weinberg model is being presented in the figure below?

A)Random mating
B)Selfing
C)Migration
D)Mutation
E)Selection

Question 10

The figure above documents the changing allelic frequency of the sinistral morph of a Lake Tangyanikan cichlid.This figure is an example of

A)positive frequency dependent selection.
B)negative frequency dependent selection.
C)overdominance.
D)balancing selection.
E)B and D

Question 11

At an underdominant locus,how will allele frequencies change through time?

A)The homozygote with the greatest fitness advantage will have its allele fixed.
B)A balanced polymorphism of both alleles will be maintained at a stable equilibrium.
C)The homozygote with the lowest fitness advantage will have its allele lost.
D)One or the other allele will be lost depending on their initial frequencies.
E)Both alleles will be lost.

Question 12

Consider a population of crickets in which the A and a alleles at a single locus control the shape of the male and female reproductive organs.Males that are AA can only mate with females that are aa,and vice versa.Heterozygous individuals can mate with either homozygous group.After many generations of selection,the two alleles will reach a(n)_________ equilibrium due to _________ frequency dependent selection.

A)stable; negative
B)balanced; negative
C)unstable; positive
D)stable; directional
E)unstable; negative

Question 13

The selection coefficient describes

A)the value of an allele after selection.
B)how many individuals survive to reproduction.
C)the fitness difference between one genotype and an alternative genotype.
D)the change in allele frequencies due to direct selection.
E)the degree of dominance of one allele relative to an alternative allele.

Question 14

Which of the following model organisms is not expected to achieve Hardy-Weinberg equilibrium?

A)Fruit fly
B)Nematode worm
C)Bacteria
D)Mouse
E)Zebrafish

Question 15

If no evolutionary force acts on a population besides mutation,genotype frequencies will

A)remain the same over time.
B)increase over time.
C)decrease over time.
D)always be in the Hardy-Weinberg proportions.
E)None of the above

Question 16

The null model for population genetics is

A)Newton's first law.
B)the competitive exclusion model.
C)cell theory.
D)the endosymbiosis theory.
E)the Hardy-Weinberg model.

Question 17

Consider a diploid population in which a single locus has only two alleles,A₁ and A₂,whose respective allele frequencies equal p and q.The summation of p+q would equal

A)0.25
B)0.5
C)1
D)1.5
E)2

Question 18

Which of the bar graphs in the figure below depicts data regarding a beneficial mutation that will become fixed most rapidly?

A)Graph A
B)Graph B
C)Graph C
D)Cannot be determined from the information provided
E)None of the above

Question 19

Assume a biallelic locus in a diploid population has the genotype frequencies: A₁A₁ = 0.59; A₁A₂ = 0.16; and A₂A₂ = 0.25.What is the observed allele frequency (p)of the A₁ allele?

A)0.59
B)0.16
C)0.25
D)0.67
E)0.33

Question 20

When a population is in a neutral equilibrium,a small change causes the population to

A)return to its starting position.
B)move farther away from its starting point.
C)remain at its displaced position.
D)A and B
E)A and C

Question 21

Lifetime fitness,as demonstrated by Cummings et al.'s work on sunflowers,is dependent on what two components?

Question 22

Consider a sample of 100 individuals sampled from a population in Hardy-Weinberg equilibrium that are genotyped at a single locus.Of these 100 individuals,25 individuals are A₁A₁ homozygotes,45 are A₁A₂ heterozygotes,and 30 are A₂A₂ homozygotes.List the observed and expected genotypic frequencies of this locus in this sample.

Question 23

In the following figure,m is the mutation rate from allele A₁,which produces a functional protein,to A₂,an allele that fails to produce a functional protein.The reverse mutation rate,n,describes the mutation rate from A₂,the nonfunctioning allele,to A₁,the functional protein allele.Why would one expect the value of m to be much higher than the value of n at this locus?

Question 24

Mating preferences drive assortative mating

A)all of the time.
B)none of the time.
C)some of the time.
D)every other time.
E)in selfing plants.

Question 25

Consider a locus in which the fitness of AA and Aa genotypes are greater than the fitness of aa genotype.In addition,this locus experiences forward mutation from the A allele to a allele.At this locus,the A allele will

A)always go to fixation.
B)always be lost.
C)never go to fixation.
D)never change.
E)None of the above

Question 26

What is the frequency of homozygous individuals in a Hardy-Weinberg population that experiences inbreeding expressed in terms of the frequencies of alleles (p,q)and the value of F.

Question 27

Disassortative mating may be beneficial because

A)it will likely reduce the probability of a deleterious recessive being expressed.
B)it will maximize the genetic diversity in the offspring.
C)it makes it easier to find a mate.
D)A and B
E)All of the above

Question 28

In pocket mice,possession of the D allele at the Mc1R locus confers dark coloration and homozygous d individuals are light in color.Why would one expect to see more D alleles in a population living on lava?

Question 29

List five assumptions of the Hardy-Weinberg equilibrium.

Question 30

After one generation of inbreeding,one would expect to see a(n)_________ in heterozygotes but no change in _________ frequencies.

Question 31

Inbreeding depression is caused by

A)a reduction in fitness caused by deleterious recessives.
B)random mating.
C)mutation-selection balance.
D)A and B
E)All of the above

Question 32

What is the term for the condition in which the heterozygote is more fit than either homozygote?

Question 33

Two gene copies are identical by descent if

A)two individuals have the same parents.
B)one allele mutates to a second allele.
C)selfing occurs.
D)they are both inherited from the same gene copy in a recent common ancestor.
E)balancing selection maintains two or more alleles.

Question 34

What phenomenon is represented in the following figure?

A)Overdominance
B)Balancing selection
C)Mutation-selection balance
D)Back mutation
E)Genetic drift

Question 35

When Takata et al.2002 examined allele and genotype frequencies at the myoglobin locus in a Japanese population,the observed and expected genotypic frequencies were very similar.Had they been very different,what could one conclude about this locus in this population?

Question 36

Pacific salmon hatch in streams and grow up out in the Pacific Ocean.At the end of their life,they mate once then die.Assuming that not all salmon survive life in the ocean and that those who do survive produce equal numbers of offspring,this would be an example of _________ selection.

Question 37

Consider a human illness in which individuals homozygous for a deleterious,recessive allele suffer from a disease with a selection coefficient of s = 0.85 (i.e.,a relative fitness of 0.15).At equilibrium,the nondeleterious allele has a population frequency of 0.95.What is the mutation rate from the healthy allele to the deleterious allele?

Question 38

As the value of F increases,so does the frequency of

A)homozygotes.
B)heterozygotes.
C)dominant alleles.
D)recessive alleles.
E)None of the above

Question 39

Name three predictions generated from the Hardy-Weinberg model.

Question 40

In the figure below,what will be the equilibrium frequency of A₁ on the island?

A)0.3
B)0.7
C)0.8
D)0.2
E)0.1

Question 41

In the island model of migration,under what condition(s)will the allele frequencies in an island population be in Hardy-Weinberg equilibrium ?

Question 42

Suppose the frequency of the A₁ allele is pᵢ = 0.4 on an island and pm = 0.8 on the mainland.If a fraction of the island population,k = .10,is replaced by migrants from the mainland each generation,what is the frequency of A₁ on the island after one generation of migration?