The genetics field that is concerned with the extent of genetic variation within a group of individuals and changes in that variation over time is ____ genetics.

population

Consider a population of cheetahs, inhabiting a protected area in Africa. In 2012, there were 112 cheetahs in this population. During that year, 60 of those animals reproduced and 48 new cubs were born. What constitutes the gene pool of the new generation made of those 48 new cubs?

Multiple choice question.

All of the alleles of all the genes in the 60 parents that had those 48 cubs

All of the alleles of all the genes that were passed from the 60 parents to the 48 new cubs

All of the alleles of all the genes in the 112 adult animals that made up the population in 2012

All of the alleles of all the genes in the 112 animals in 2012 plus all of the alleles of all the genes in the 48 newborn animals

All of the alleles of all the genes that were passed from the 60 parents to the 48 new cubs

Reason:

Individuals of one generation constitute a gene pool. Only those parental genes passed to the 48 new cubs will be part of the new gene pool.

True or false: In a large population made of several local populations, the likelihood of breeding within a local population is roughly the same as the likelihood of breeding with an individual from a different local population.

False

Reason:

Since local populations are often separated by moderate geographic barriers, the likelihood of finding a mate within a local population or deme is actually much higher than the likelihood of breeding with a member of another deme.

Select all that apply

Which of the following are factors that can cause a change in the size of a population from one generation to the next?

Multiple select question.

Predators

Diseases

Natural disasters

A new mutation

Predators

Diseases

Natural disasters

Fill in the blank question.

Most of the traits in a healthy natural population exhibit some level of variation, or ____, that is, they are found in two or more forms.

polymorphism

Population genetics is concerned with the ______.

Multiple choice question.

distances between genes on the same chromosomes

cloning of agriculturally-important organisms

outcome of specific genetic crosses

extent of genetic variation within a group of individuals

extent of genetic variation within a group of individuals

Consider a population, for which you know the allele composition of three genes. Gene A has three alleles in the following proportions: A1 - 34.4%, A2 - 30%, A3 - 35.6%. Gene B has two alleles in the following proportions: B1 - 67.1%, B2 - 32.9%. Gene C has two alleles in the following proportions: C1 - 99.2%, C2 - 0.8%. Which of those genes is(are) polymorphic?

Multiple choice question.

C only

A and B only

A, B and C

A only

A and B only

Reason:

Gene C is monomorphic.

The ____ ____ of a population consists of all of the alleles of every gene in all of the individuals of that population.

Blank 1: gene, allele, or allelic

Blank 2: pool or frequency

Consider the following types of changes in DNA: a deletion of part of a gene (A); a duplication of a region in a gene (B); a replacement of one nucleotide with a different one (C). Which of those changes can cause polymorphisms in a population?

Multiple choice question.

C only

A, B, and C

A and C only

A and B only

A, B, and C

Reason:

A substitution as described for change C also causes a polymorphism.

Consider a population of crickets that occupies two fields separated by a road and two ditches. Crickets inhabiting the two fields comprise two local populations, or demes. What is the likelihood that a cricket will reproduce within its own deme compared to the likelihood a cricket will reproduce with a cricket from the other deme?

Multiple choice question.

The likelihood of reproducing within a deme is much lower than the likelihood of reproduction between demes.

The likelihood of reproducing within a deme is much higher than the likelihood of reproduction between demes.

Since the two demes belong to the same population, the likelihood of reproducing within and between demes is the same.

The likelihood of reproducing within a deme is much higher than the likelihood of reproduction between demes.

Reason:

Members of a local population are more likely to breed among themselves.

What is the most common type of polymorphism found in natural populations, including human populations?

Multiple choice question.

SNPs

Gene duplications

Gene deletions

Gene inversions

SNPs

Select all that apply

Natural populations are dynamic entities. From the list below choose features of populations that can change from one generation to the next.

Multiple select question.

Geographic location

Species diversity

Size

Genetic composition

Geographic location

Size

Genetic composition

How is the allele frequency of a population calculated?

Multiple choice question.

The number of copies of the allele in the population is multiplied by the total number of all the alleles for the same gene in the population.

The number of individuals that have this allele in the population is divided by the total number of individuals in the population.

The number of copies of the allele in the population is divided by the total number of all the alleles for the same gene in the population.

The number of copies of the allele in the population is divided by the total number of all the alleles for all genes in the population.

The number of copies of the allele in the population is divided by the total number of all the alleles for the same gene in the population.

Reason:

Allele frequencies for each gene are calculated separately.

Reason:

The total number of alleles in the population must be considered. Except for X-linked genes in males, individuals will have two copies of each allele.

When scientists study populations, they typically observe high levels of variation in many of the traits that characterize a species. In genetics, variations in traits at the population level are known as ______.

Multiple choice question.

demes

mutations

alleles

polymorphisms

polymorphisms

Consider a population and a gene that has two alleles in this population, designated as D and d. If you divide the number of individuals with the genotype DD by the total number of individuals in the population, you will calculate the ______.

Multiple choice question.

allele frequency of the D allele

genotype frequency of the DD genotype

genotype frequency of the D allele

genotype frequency of the DD genotype

Reason:

Be sure to distinguish between frequencies of alleles and genotypes.

In population genetics, a gene that exists as two or more alleles in a population is a(n) ______ gene, while one that exists predominantly as a single allele is a(n) ______ gene.

Multiple choice question.

monomorphic; polymorphic

polymorphic; monomorphic

polymorphic; monomorphic

Reason:

In population genetics, a gene that exists as two or more alleles in a population is a polymorphic gene, while one that exists predominantly as a single allele is a monomorphic gene.

In a population of lizards, a gene is found in two forms, B, and b. The number of animals with the three possible genotypes for this gene is as follows: BB - 24; Bb - 42; bb - 9. What is the frequency of the B allele in this population?

Multiple choice question.

0.44

0.5

0.6

0.32

0.6

Reason:

BB individuals contribute two B alleles while Bb individuals contribute one B allele. Add those contributions together and divide by the total number of alleles.

Fill in the blank question.

A change in one nucleotide in a gene is also known as a ____-nucleotide ____, or, SNP.

single; polymorphism

The sum of the frequencies of all of the alleles of a particular gene in a population is always

Blank 1: 1, 100%, or one

A large, healthy, natural population typically exhibits a ______ level of SNPs.

Multiple choice question.

moderate to low

very low

high

high

Reason:

The most common type of polymorphism found in natural populations, including human populations, are SNPs.

The Hardy-Weinberg equilibrium is a mathematical expression which predicts that, when certain requirements are met, the allele and genotype frequencies of a gene in a population ______.

Multiple choice question.

tend to become equally distributed over the course of many generations (for example, with two alleles, both alleles' frequencies will become 0.5)

do not change over the course of many generations

randomly change over the course of many generations

do not change over the course of many generations

Reason:

Allele and genotype frequencies become constant but not necessarily equally distributed.

Consider a population and a gene that has two alleles in this population, designated as E and e. If you divide the number of all the copies of the e allele in the population by the total number of copies of both alleles (E and e) in the population, you will calculate the ______.

Multiple choice question.

allele frequency of the E allele

genotype frequency of the ee genotype

allele frequency of the e allele

genotype frequency of the e allele

allele frequency of the e allele

Reason:

The calculation "allele frequency of the E allele" would reflect the frequency of the e allele.

Reason:

A genotypic frequency is number of individuals with the ee genotype divided by the total number of individuals in the population.

You are studying a very rare disease, which affects only 1 in 40,000 individuals. The disease is caused by a recessive allele, such that only individuals with homozygous recessive genotypes are affected. What is the expected frequency of heterozygous carriers in this population?

Multiple choice question.

About 5%

About 0.005%

About 2%

About 1%

About 1%

Reason:

In this problem q²=1/40,000. Use this information to calculate q and p. The frequency of heterozygous carriers is 2pq.

How can we calculate the frequency of a specific genotype in a population?

Multiple choice question.

The total number of individuals in the population is divided by the number of individuals with this genotype in the population.

The number of individuals with this genotype in the population is divided by the number of individuals with all other genotypes in the population.

The number of individuals with this genotype in the population is divided by the total number of individuals in the population.

The number of individuals with this genotype in the population is divided by the total number of all alleles for this gene in the population.

The number of individuals with this genotype in the population is divided by the total number of individuals in the population.

Reason:

The number of individuals with the genotype must be divided by the number of individuals in the whole population.

Which of the following is an accurate depiction of the Hardy-Weinberg equation for a gene with two alleles?

Multiple choice question.

p ² + q ² = 2pq

p ² + pq + q ² = 1

p ² + 2pq + q ² = 1

p ² + 2pq + q ² = 1

In a population of frogs, a gene is found in two forms - D, and d. The numbers of individuals with different genotypes for that gene are 30 (DD), 18 (Dd), and 12 (dd). What is the frequency of the heterozygous genotype?

Multiple choice question.

0.43

0.65

0.30

0.18

0.30

Reason:

Genotype frequency = # individuals with a particular genotype/Total # in population. Thus, 18/60 = 0.3.

You are studying a bird population and a gene that has 2 alleles, A, which is found at a frequency of 0.4, and a, which is found at a frequency of 0.6. If this population was in Hardy-Weinberg equilibrium, what would be the probability of the genotype aa in the next generation?

Multiple choice question.

0.48

0.24

1

0.36

0.36

Reason:

The frequency of the aa genotype is q²= 0.6 x 0.6.

A gene is present in the form of three alleles in a population, G, g ₁, and g ₂. If the frequency of the G allele is 0.6, and the frequency of the g ₁ allele is 0.2, then what is the frequency of the g ₂ allele?

Multiple choice question.

0.8

0.4

1

0.2

0.2

Reason:

The sum of the frequencies must equal 1.

The Hardy -Weinberg equilibrium is used as a null hypothesis, i.e., if a population is in Hardy-Weinberg equilibrium, then ______.

Multiple choice question.

evolutionary change is occurring in this population

all of the different alleles for a gene in a population have the same frequency

evolutionary change is not occurring in this population

evolutionary change is not occurring in this population

Select all that apply

Which of the following are conditions that must be met in order for a population to be in Hardy-Weinberg equilibrium for a specific gene of interest?

Multiple select question.

The population must be large enough so that no genetic drift is occurring.

All of the different genotypes (with respect to the gene of interest) must have equal reproductive success (no selection).

Immigration and emigration rates must be equal, resulting in no net movement of organisms.

No new mutations should be appearing in the gene of interest.

The population must be large enough so that no genetic drift is occurring.

All of the different genotypes (with respect to the gene of interest) must have equal reproductive success (no selection).

No new mutations should be appearing in the gene of interest.

You are studying a rare disease, which affects 1 out of 10000 individuals. The disease is caused by a gene with two alleles: D, and d. Individuals with a dd genotype are affected, while individuals with a Dd phenotype are unaffected carriers. What is the expected frequency of unaffected carriers in the population, assuming this gene is in Hardy-Weinberg equilibrium?

Multiple choice question.

Approximately 0.02%

Approximately 1%

Approximately 98%

Approximately 2%

Approximately 2%

Reason:

In this problem q²=1/10000. Use this information to calculate q and p. The frequency of heterozygous carriers is 2pq.

If a population is in Hardy-Weinberg equilibrium for a gene with two alleles (G and g), and the frequency of the g allele is very low, we can predict that most of the organisms in this population will have the _____ genotype.

Multiple choice question.

GG

gg

Gg

GG

Reason:

The low frequency of the g allele will affect both the gg and Gg genotype frequencies.

In order to derive the Hardy-Weinberg equation, the two scientists assumed that ______ population's gene pool..

Multiple choice question.

gametes are chosen in a specific non-random sequence from the

gametes are independently chosen at random from the

there is an equal number of gametes for each allele in the

there is an infinite number of all types of gametes in the

gametes are independently chosen at random from the

Reason:

The Hardy-Weinberg equilibrium assumes that two gametes are chosen at random from the gene pool.

You are studying a population and a gene within that population with two alleles, H and h. After determining the genotypes of all the individuals in the population you calculate the observed and expected numbers of individuals for the three genotypes as follows. Observed individuals: HH - 87; Hh - 145; hh - 68. Expected individuals: HH - 75; Hh - 150; hh - 75. What is the Chi-square value calculated based on these observations?

Multiple choice question.

2.74

218

0.73

2.55

2.74

Reason:

You calculated the differences between observed and expected (O-E)² but you did not divide them by E before summing all of them.

A gene is found in two forms in a population of plants. The two alleles are denoted as B, and b. You determine that the frequency of the B allele in this population is 0.2. If this population was in a Hardy-Weinberg equilibrium, calculate the probability of a heterozygote in the next generation.

Multiple choice question.

0.32

0.04

0.64

0.16

0.32

Reason:

Calculate 2pq for p=0.2 and q=1-p.

The sum of the frequencies of all of the alleles of a particular gene in a population is always

1

When the hypothesis that the allele and genotype frequencies are in Hardy-Weinberg equilibrium is rejected, it can be stated that the population is in

disequilibrium

Select all that apply

Consider a population of a hypothetical animal, whose fur color is determined by a single gene, called Col. From the list below choose all conditions that must be met in order for this population to be in Hardy-Weinberg equilibrium for the Col gene.

Multiple select question.

Low to moderate levels of genetic drift

No natural selection

Animals in the population mate randomly, regardless of their genotype for the Col gene

No new mutations in the Col gene

No new mutations in any gene

No natural selection

Animals in the population mate randomly, regardless of their genotype for the Col gene

No new mutations in the Col gene

Reason:

It is only the gene of interest that does not incur any new mutations.

The change in a population's gene pool from one generation to the next is known as ______.

Multiple choice question.

microevolution

natural selection

Hardy-Weinberg equilibrium

evolutionary drift

microevolution

Which of the following describes a situation, in which the predominant genotype in a population in Hardy-Weinberg equilibrium is the heterozygote? Assume that the gene of interest has only two alleles: G , and g .

Multiple choice question.

The allele frequencies of G and g are very low.

The allele frequencies of G and g are very high.

The allele frequencies of both G and g are intermediate in value.

The allele frequency of g is low.

The allele frequencies of both G and g are intermediate in value.

Reason:

When the allele frequencies of g and G are intermediate in value, the heterozygote predominates.

Reason:

When the allele frequency of g is low, the GG genotype predominates. When the allele frequencies of g and G are intermediate in value, the heterozygote predominates.

Which of the following phenomena is responsible for introducing new genetic variation in a population?

Multiple choice question.

Mutation

Random mating

Genetic drift

Non-random mating

Natural selection

Mutation

Reason:

Mutation is a constant source of new genetic variation. Evolutionary mechanisms, such as natural selection and genetic drift, can act to alter existing genetic variation.

You are studying a population and a gene within that population with two alleles, M and m. After determining the genotypes of all the individuals in the population you calculate the observed and expected numbers of individuals for the three genotypes as follows. Observed individuals: MM - 200; Mm 123; mm - 14. Expected individuals: MM - 202; Mm - 117; mm - 17. What is the Chi-square value calculated based on these observations?

Multiple choice question.

0.002

54

0.86

0.98

0.86

Reason: 0.002

You calculated the differences between observed and expected (O-E)² but you divided them by O instead of E before summing all of them.

Reason: 54

You calculated the differences between observed and expected (O-E)² but you did not divide them by E before summing all of them.

Reason: 0.98

You calculated the differences between observed and expected (O-E)² but you divided them by O instead of E before summing all of them.

Fill in the blank question.

According to the theory of ____ ____, individuals with alleles leading to greater reproductive success will be more likely to produce offspring and pass those alleles to the next generation.

natural selection

A population would be described as being in ______ if a high chi-square value is obtained when testing whether the allele and genotype frequencies are in Hardy-Weinberg equilibrium.

Multiple choice question.

disequilibrium

steady state

equilibrium

exponential growth

disequilibrium

Factors such as an individual's fertility and the ability to find a mate contribute to

reproductive success

Microevolution is best described as ______.

Multiple choice question.

the evolution of a single gene

the change in a population's gene pool from generation to generation

a random change in the genetic variation of a small population

the differential survival of members of a population with a certain genotype

the change in a population's gene pool from generation to generation

Reason:

Genetic drift refers to random changes in variation.

Two types of factors can govern microevolution. On one hand, mutation is a constant source of new genetic variation. On the other hand, mechanisms, such as natural selection and genetic drift, can act to alter existing genetic variation. How do those two types of factors compare in terms of the magnitude of their effect on allele frequencies in a population?

Multiple choice question.

Mutations have a negligible effect on allelic frequencies, while mechanisms, such as natural selection and drift, can have a dramatic effect.

Both mutations, and mechanisms, such as selection and drift, can dramatically and quickly alter allelic frequencies in a population.

Mutations can have a dramatic effect on allelic frequencies, even when mechanisms, such as natural selection and drift, are not operating.

Mutations have a negligible effect on allelic frequencies, while mechanisms, such as natural selection and drift, can have a dramatic effect.

Reason:

Mutation is a constant source of new genetic variation. Evolutionary mechanisms, such as natural selection and genetic drift, can act to alter existing genetic variation.

Which of the following is the best definition of Darwinian fitness as it relates to population genetics?

Multiple choice question.

The relative (compared to other genotypes) likelihood that a genotype will contribute alleles to the next generation

The frequency of the genotype that is most likely (compared to other genotypes) to contribute alleles to the next generation

The likelihood that a genotype will contribute to the next generation, relative to the dominant homozygous genotype

The relative (compared to other genotypes) likelihood that a genotype will contribute alleles to the next generation

Natural selection is the phenomenon in which certain phenotypes have ______ than other phenotypes.

Multiple choice question.

greater reproductive success

longer lifetimes

more success in gathering nutrients

perfect adaptations to the environment

greater reproductive success

Consider a population and a gene present in this population as two alleles: F, and f. For every 10 Ff individuals that survive to reproduce, 8 FF and 4 ff individuals survive to reproduce as well. If we assume that all individuals that survive to reproduce have roughly the same number of offspring, what is the relative fitness of the FF genotype in this case?

Multiple choice question.

0.8

0.4

1.25

1.0

0.8

Reason: 0.4

This represents the fitness of the ff individuals, where 4/10 survive to reproduce.

Reason: 1.0

This represents the fitness of the Ff individuals, where 10/10 survive to reproduce.

Select all that apply

Which factors contribute to reproductive success?

Multiple select question.

Having characteristics that make an individual better adapted to the environment

The ability to live a long life

Having high fertility

Living in a small population

The ability to find a mate

Having characteristics that make an individual better adapted to the environment

Having high fertility

The ability to find a mate

Reason:

Reproduction occurs over only a portion of the life span

Select all that apply

Which of the following are likely reasons for differences in the reproductive success of different genotypes in a population?

Multiple select question.

Some genotypes are more likely to survive to reproductive age than others.

Some genotypes are more likely to continue to live after surviving to reproductive age.

Some genotypes are more susceptible to genetic drift than others.

Some genotypes are more likely to find mates than others.

Some genotypes are more fertile than others.

Some genotypes are more likely to survive to reproductive age than others.

Some genotypes are more likely to find mates than others.

Some genotypes are more fertile than others.

In ____ selection, individuals at one extreme of a phenotypic distribution are more likely to survive and reproduce in a particular environment.

directional

The relative (compared to other genotypes) likelihood that a genotype will contribute its alleles to the next generation is known as

Darwinian fitness

Which of the following is a situation in which directional selection may be observed?

Multiple choice question.

In a population with a continuous phenotypic distribution, two extreme phenotypes are more fit than the intermediate phenotype.

Heterozygotes in a population exhibit fitness higher than the fitness of any of the homozygotes.

A new allele, which promotes higher fitness in organisms that carry it, is introduced in a population (for example, by a random mutation).

A new allele, which promotes higher fitness in organisms that carry it, is introduced in a population (for example, by a random mutation).

Consider a population and a gene present in this population as two alleles: D, and d. For every 100 dd individuals that survive to reproduce, 18 DD and 99 Dd individuals survive to reproduce as well. Which of these three genotypes has the highest Darwinian fitness and what is its value (w)? Assume that all individuals that survive to reproduce have roughly the same number of offspring.

Multiple choice question.

DD, w _DD= 1.0

DD, w _DD= 18

dd, w _dd= 100

dd, w _dd= 1.0

Dd, w _Dd= 0.98

dd, w _dd= 1.0

Reason:

w _DD= 0.18 since 18 DD individuals survive for every 100 dd individuals that survive.

Reason:

w _Dd= 0.99 since 99 Dd individuals survive for every 100 dd individuals that survive.

A gene is present in a population in two forms. The frequency of allele G is 0.3, while the frequency of allele g is 0.7. The most fit genotype is gg, with a relative fitness of 1. The relative fitness of the heterozygotes is 0.6, and that of the dominant homozygotes is 0.3. In this case of directional selection (which favors the g allele), what would the frequencies of the two alleles (G and g) be after one generation?

Multiple choice question.

G - 0.40; g - 0.60

G - 0.25; g - 0.75

G - 0.20; g - 0.80

G - 0.50; g - 0.50

G - 0.20; g - 0.80

Reason:

First, you have to calculate the mean fitness of the population. Once you have that, calculate the frequencies of genotypes in the next generation by taking the Hardy-Weinberg predicted formula, multiplying them by the relative fitness and dividing by the mean fitness. For example, for the GG genotype, you would calculate p ² w _GG/(mean fitness). After you have calculated the expected genotype frequencies, calculate the allele frequencies.

Which of the following is not a reason for differences in the reproductive success of different genotypes in a population?

Multiple choice question.

Some genotypes can be more fertile.

Some genotypes can be more likely to find mates.

Certain genotypes can be more likely to survive to reproductive age.

Certain genotypes are more likely to continue to live after surviving to reproductive age.

Certain genotypes are more likely to continue to live after surviving to reproductive age.

Reason:

Reproductive success depends on the ability to survive and reproduce.

Sometimes individuals at one extreme of a phenotypic distribution are favored in a particular environment, for example, selection will strongly favor insects that have very high resistance to an insecticide. In such cases, the type of selection that operates is ______ selection.

Multiple choice question.

diversifying

directional

stabilizing

directional

The ____ ____ of a population is the sum of the frequencies of all genotypes, each one multiplied by its respective relative fitness.

mean fitness

You are studying a population of birds that has recently become established on an island some 1,000 km from the mainland. On the mainland, these birds mostly consume fleshy fruits, however, on the island they are forced to eat nuts that have to be cracked open with a strong beak. What type of selection is most likely to occur for genes that determine the size and strength of the beak in these birds?

Multiple choice question.

Disruptive selection

Stabilizing selection

Directional selection

Directional selection

A population is undergoing directional selection for a gene with two alleles: G, and g. The most fit genotype is GG (relative fitness 1), while the Gg and gg genotypes both have relative fitnesses of 0.5. Which of the following is expected to happen after several generations (assuming that the environment, in which this population lives, is not changing)?

Multiple choice question.

The relative fitnesses of the Gg and gg phenotypes will decrease.

The mean fitness of the population will increase.

The relative fitness of the GG genotype will increase.

The mean fitness of the population will decrease.

The mean fitness of the population will increase.

Reason:

Relative fitness will not change because the environment is unchanging.

Reason:

The relative fitness of the GG genotype will increase.

This genotype has the highest fitness.

In ____ selection, natural selection favors the maintenance of two or more alleles in a population. An example of that is the phenomenon of heterozygote advantage.

balancing

A population is undergoing a directional selection for a gene with two alleles, A (with a frequency of 0.4), and a, (with a frequency of 0.6). The relative fitness values for the three genotypes are as follows: w _AA=1, w _Aa=0.5, and w _aa=0.5. What would be the expected frequencies of the two alleles after one generation?

Multiple choice question.

A - 0.48; a - 0.52

A - 0.66; a - 0.34

A - 0.60; a - 0.40

A - 0.50; a - 0.50

A - 0.48; a - 0.52

Reason:

First, you have to calculate the mean fitness of the population. Once you have that, calculate the frequencies of genotypes in the next generation by taking the Hardy-Weinberg predicted formula, multiplying them by the relative fitness and dividing by the mean fitness. For example, for the AA genotype, you would calculate p ² w _AA/(mean fitness). After you have calculated the expected genotype frequencies, calculate the allele frequencies.

Fill in the blank question.

Consider a single gene with two alleles in a population of wild birds. A situation in which the heterozygotes for that gene have higher fitness than the two homozygote genotypes is known as ____ ____. In these situations, an equilibrium is reached, in which both alleles of the gene are maintained in the population.

heterozygote advantage

The mean fitness of a population undergoing directional selection is ______.

Multiple choice question.

less than 1

more than 1

always 1

less than 1

Reason:

The value may not be equal to 1 when the population is changing during natural selection.

What does the selection coefficient measure?

Multiple choice question.

The extent to which a genotype is selected for

The difference between the fitnesses of the heterozygotes and the homozygotes

The difference between the fitnesses of the most fit and the least fit genotypes

The extent to which a genotype is selected against

The extent to which a genotype is selected against

In a population that is undergoing directional selection, the mean fitness of the population ______.

Multiple choice question.

stays constant from generation to generation

increases with each generation

decreases with each generation

increases with each generation

Reason:

Natural selection raises the mean fitness of the population.

Which of the following formulas describe the situation in which a population undergoing balancing selection due to heterozygote advantage reaches equilibrium? In this case, we have a single gene, with two alleles, B and b, with frequencies of p (for the B allele) and q (for the b allele).

Multiple choice question.

w _BB p = w _bb q

s _bb p = s _BB q

s _BB p = s _bb q

s _BB = w _BB and s _bb = w _bb

s _BB p = s _bb q

Reason:

s _bb is multiplied by q and s _BB is multiplied by p.

Reason:

The relative fitness values (w) are used to calculate the selection coefficients (s), where s=1-w.

In certain populations, natural selection can favor the maintenance of 2 or more alleles in a population. An example of this is ______ selection.

Multiple choice question.

directional

balancing

equilibrium

single gene

balancing

Reason:

Directional selection occurs when one allele confers a favorable advantage over another.

The Hb ^S allele for the human β-globin gene is found in relative high frequencies in certain human populations living in areas where malaria is endemic, despite the fact that individuals homozygous for this allele exhibit sickle cell anemia. What explains this observation?

Multiple choice question.

The homozygous individuals for the sickle cell allele (Hb ^S Hb ^S) are highly resistant to malaria.

Sickle cell anemia is a much less dangerous disease than malaria.

The heterozygous genotype (Hb ^A Hb ^S) is more resistant to malaria than either of the homozygote genotypes.

The heterozygous genotype (Hb ^A Hb ^S) is more resistant to malaria than either of the homozygote genotypes.

Reason:

Individuals with the heterozygous genotype (Hb ^A Hb ^S) are resistant to malaria.

When the heterozygotes for a specific gene have higher fitness than either of the corresponding homozygous genotypes (assume a single gene with two alleles), we are observing a situation called ______.

Multiple choice question.

homozygote disadvantage

equilibrium selection

heterozygote advantage

heterozygote equilibrium

heterozygote advantage

Fill in the blank question.

In certain cases, the fitness of a genotype may be dependent on its frequency. When the fitness of a genotype decreases when its frequency increases, the pattern of natural selection is referred to as ____ ____-dependent selection.

negative frequency

Which of the following is not a reason for differences in the reproductive success of different genotypes in a population?

Multiple choice question.

Some genotypes can be more likely to find mates.

Certain genotypes can be more likely to survive to reproductive age.

Certain genotypes are more likely to continue to live after surviving to reproductive age.

Some genotypes can be more fertile.

Certain genotypes are more likely to continue to live after surviving to reproductive age.

Reason:

Reproductive success depends on the ability to survive and reproduce.

Genotypes that have lower relative fitnesses are selected against. The extent of that selection is measured by s, the

selective coefficient

You are studying a gene with two alleles, A, and a, in a population of plants. The relative fitness coefficients of the three genotypes for this gene are as follows: w _AA = 0.5; w _Aa = 1; w _aa = 0.3. If this population is undergoing balancing selection due to heterozygote advantage, what would the expected equilibrium frequencies of A and a be?

Multiple choice question.

A = 0.38; a = 0.63

A = 0.58; a = 0.42

A = 0.67; a = 0.33

A = 0.58; a = 0.42

Reason:

p = Allele frequency of A = S _aa / S _AA + S _aa. Thus, 0.7 / 0.5 + 0.7 = 0.58. Frequency for aa = 1 - frequency for AA. 1 - 0.58 = 0.42.

Which type of selection is also known as diversifying selection because it tends to favor the survival of two or more different phenotypes in a heterogeneous environment?

Multiple choice question.

Stabilizing selection

Directional selection

Disruptive selection

Disruptive selection

Reason:

Stabilizing selection favors the survival of an intermediate phenotype.

Which of the following best explains the high prevalence of the Hb ^S allele of the human β-globin gene in populations living in areas of high malaria prevalence?

Multiple choice question.

This gene is under balancing selection due to heterozygote advantage in those areas.

This gene is under directional selection for the Hb ^S allele in those areas.

This gene is under negative frequency-dependent selection in those areas.

This gene is under balancing selection due to heterozygote advantage in those areas.

Reason:

Individuals that are homozygous for the Hb ^S allele are selected against.

Some traits are quantitative, i.e. they are determined by multiple genes and exhibit a range of phenotypes. For some of those traits, the fitness values for particular genotypes may be higher in one environment and lower in another. When populations with such traits inhabit heterogeneous environments, multiple alleles can be maintained through the action of ______.

Multiple choice question.

balancing

equilibrium

diversifying

directional

diversifying

Reason:

Balancing selection relates to alleles of one gene.

Which of the following best describes the relationship between a genotype's fitness and its frequency in negative frequency-dependent selection?

Multiple choice question.

As the frequency of a genotype increases, its fitness also increases.

As the frequency of heterozygotes increases, the fitness of both homozygote genotypes decreases.

As the frequency of a genotype increases, its fitness decreases.

As the frequency of a genotype increases, its fitness decreases.

Reason:

Rare individuals have a higher fitness than more common individuals in this type of selection.

____ selection acts on quantitative traits determined by multiple genes. In this type of selection, individuals with intermediate phenotypes have higher fitness and are selected for, while extreme phenotypes are selected against.

Stabilizing

The weight of a human baby at birth is a quantitative trait determined by the activity of many genes. Babies with very low or very high birth weights have a decreased chance of survival, while babies with intermediate birth weights have much better chances of survival. What can you hypothesize about the genetic diversity of genes that determine birth weight in humans?

Multiple choice question.

They are under a balancing selection, which should increase their genetic diversity.

They are under stabilizing selection, which should decrease their genetic diversity.

They are under disruptive selection, which should increase their genetic diversity.

They are under stabilizing selection, which should decrease their genetic diversity.

In disruptive selection, ______.

Multiple choice question.

the heterozygote genotype is selected for, while both homozygous genotypes are selected against

two or more alleles are maintained in a heterogeneous environment

one allele is selected for while all other alleles are selected against

two or more alleles are maintained in a heterogeneous environment

Reason:

Stabilizing selection favors the heterozygous genotype.

Disruptive selection typically acts on ______.

Multiple choice question.

single genes that have at least 5 or more alleles

quantitative traits that are influenced by more than one gene

monomorphic traits influenced by two or more genes

quantitative traits that are influenced by more than one gene

Reason:

This type of selection works on polygenic traits with a continuum of phenotypes.

In certain cases, the fitness of a genotype may be dependent on its frequency. When the fitness of a genotype decreases when its frequency increases, the pattern of natural selection is referred to as ____ ____-dependent selection.

Blank 1: negative

Blank 2: frequency

In their studies of the medium ground finches of Daphne Major, the Grants determined that differences in beak sizes of finches are due to genetic differences in the population. Which of the following was evidence for that?

Multiple choice question.

The Grants were able to determine the exact gene that codes for beak depth in those birds.

When the values of beak depth for all the birds on the island were summarized as a histogram, a bell curve was produced.

The depth of the beak was transmitted from parents to offspring regardless of environmental conditions.

The range of variation was too narrow to be explained solely by variations in environmental conditions.

The depth of the beak was transmitted from parents to offspring regardless of environmental conditions.

Which type of selection tends to select against extreme phenotypes for a quantitative trait, because individuals with intermediate phenotypes have the highest relative fitness values?

Multiple choice question.

Stabilizing selection

Negative frequency-dependent selection

Disruptive selection

Directional selection

Stabilizing selection

Reason:

Directional selection favors one of the extreme phenotypes.

The Grants were able to demonstrate that natural selection occurs in a population of medium ground finches, because when they experience a very dry year, which severely reduces the supply of smaller seeds, ______.

Multiple choice question.

their offspring, which become adults during the next year, have, on average, larger beaks

their offspring, which become adults during the next year, have, on average, smaller beaks

the average beak size in the population remains relatively constant

their offspring, which become adults during the next year, have, on average, larger beaks

Reason:

In the dry years, the finches ate larger, drier seeds in order to survive.

Stabilizing selection typically acts on quantitative traits determined by multiple genes. Does stabilizing selection have an effect on the genetic diversity of those genes and if so, what type of effect?

Multiple choice question.

Yes, stabilizing selection tends to increase the genetic diversity of those genes.

Yes, stabilizing selection tends to decrease the genetic diversity of those genes.

No, stabilizing selection typically does not affect the genetic diversity of those genes.

Yes, stabilizing selection tends to decrease the genetic diversity of those genes.

Reason:

Stabilizing selection tends to eliminate alleles that cause a greater variation in phenotypes.

The term genetic ____ refers to any random change in the frequencies of alleles in a population.

drift

You are observing two populations of the same animal species. Population 1 consists of 46 individuals, while population 2 consists of 3325 individuals. Which population is more susceptible to genetic drift?

Multiple choice question.

Population 2 is more susceptible.

Population 1 is more susceptible.

Since genetic drift is random, population size doesn't matter, so both populations are equally susceptible.

Population 1 is more susceptible.

Which of the following formulas allows us to calculate the expected number of mutations in a gene in a population?

Multiple choice question.

Expected number of new mutations = 1/2N

Expected number of new mutations = 2Nμ

Expected number of new mutations = Nμ

Expected number of new mutations = 2Nμ

Select all that apply

How did the Grants study natural selection in medium ground finches on the island of Daphne Major?

Multiple select question.

They measured several inherited traits over many years.

They measured several traits that appeared to be strongly affected by the availability of food (e.g. weight, fat content, etc.).

They determined if changes in environmental conditions (e.g., droughts) resulted in changes in heritable traits in subsequent generations.

They measured several inherited traits over many years.

They determined if changes in environmental conditions (e.g., droughts) resulted in changes in heritable traits in subsequent generations.

The Grants studied medium ground finches in Daphne Major for several decades. One of the traits they measured was beak depth. Birds with bigger beaks can crush bigger seeds, but have difficulties handling smaller seeds. Birds with smaller beaks are very good at handling small seeds, but cannot easily crush bigger seeds. When the island experiences a severe drought, plants produce fewer small seeds, and relatively more large, drier seeds. According to the Grants what would be the effect of a severe dry season on the finch population?

Multiple choice question.

The average beak size of birds during the dry year should be smaller.

The average beak size of birds in the year immediately following the dry year should be smaller.

The average beak size of birds during the dry year should be larger.

The average beak size of birds in the year immediately following the dry year should be larger.

The average beak size of birds in the year immediately following the dry year should be larger.

Reason:

The average beak size of birds in the year immediately following the dry year should be larger.

Genetic drift is the _____ in a population.

Multiple choice question.

decrease in the number of alleles

non-random change of allele frequencies

decrease of allele frequencies

random change of allele frequencies

random change of allele frequencies

What is the probability of elimination due to genetic drift of a newly arising allele in a population of 100 individuals?

Multiple choice question.

0.5%

80.0%

1%

99.5%

99.5%

Reason:

Subtract the probability of fixation from 1 to find the probability of elimination.

Reason:

This is the probability of fixation. Subtract this value from 1 to find the probability of elimination.

If genetic drift is followed over a great many generations, what is its expected effect on allele frequencies?

Multiple choice question.

Alleles are either lost (frequency of 0%) or fixed (frequency of 100%) in the populations.

Over many generations, genetic drift tends to make the frequencies of all alleles of a particular gene the same.

The ultimate effect of genetic drift over many generations is always loss of alleles.

Alleles are either lost (frequency of 0%) or fixed (frequency of 100%) in the populations.

Reason:

Allele frequencies vary randomly and some alleles are lost and others fixed over time.

Is the size of a population related to the average number of generations needed to achieve fixation of a newly appeared mutation, and how?

Multiple choice question.

The larger the population, the more generations will be required, on average, to achieve fixation of a new allele.

The smaller the population, the more generations will be required, on average, to achieve fixation of a new allele.

The size of the population is not related to the number of generation required to achieve fixation of a new allele.

The larger the population, the more generations will be required, on average, to achieve fixation of a new allele.

Reason:

Fixation takes much longer in large populations.

A population of small insects consists of 500,000 individuals. The mutation rate for a gene in this species is 0.00001 mutations per gene per generation. What is the expected number of new mutations in this population in the next generation?

Multiple choice question.

20

5

100

10

10

Reason:

Solve the equation 2Nμ for a population of 500,000 with a mutation rate of 0.00001.

In their studies of the medium ground finches of Daphne Major, the Grants determined that differences in beak sizes of finches are due to genetic differences in the population. Which of the following was evidence for that?

Multiple choice question.

The range of variation was too narrow to be explained solely by variations in environmental conditions.

The depth of the beak was transmitted from parents to offspring regardless of environmental conditions.

When the values of beak depth for all the birds on the island were summarized as a histogram, a bell curve was produced.

The Grants were able to determine the exact gene that codes for beak depth in those birds.

The depth of the beak was transmitted from parents to offspring regardless of environmental conditions.

Reason:

The depth of the beak was transmitted from parents to offspring regardless of environmental conditions.

What is the probability of fixation due to genetic drift of a newly arising allele in a population of 1000 individuals?

Multiple choice question.

0.1%

5%

1%

0.05%

0.05%

Reason:

Substitute 1000 for N in the formula: Probability of fixation = 1/2N.

Reason:

Substitute 1000 for N in the formula: Probability of fixation = 1/2N.

Population A

Reason:

Fixation takes much longer in larger populations.

Which of the following formulas allows us to calculate the expected number of mutations in a gene in a population?

Multiple choice question.

Expected number of new mutations = Nμ

Expected number of new mutations = 2Nμ

Expected number of new mutations = 1/2N

Expected number of new mutations = 2Nμ

A healthy population can become highly susceptible to genetic drift if its size is dramatically reduced due to natural phenomena, such as earthquakes or droughts. This is known as the ______ effect.

Multiple choice question.

founder

assortative

bottleneck

inbreeding

bottleneck

Select all that apply

How did the Grants study natural selection in medium ground finches on the island of Daphne Major?

Multiple select question.

They determined if changes in environmental conditions (e.g., droughts) resulted in changes in heritable traits in subsequent generations.

They measured several inherited traits over many years.

They measured several traits that appeared to be strongly affected by the availability of food (e.g. weight, fat content, etc.).

They determined if changes in environmental conditions (e.g., droughts) resulted in changes in heritable traits in subsequent generations.

They measured several inherited traits over many years.

A population that has experienced a bottleneck is highly susceptible to genetic drift ______.

Multiple choice question.

during the initial bottleneck and during the generations following the bottleneck when the population size is small

during the initial bottleneck, but also during the generations following it and even after the population recovers to its pre-bottleneck size

only during the initial bottleneck

during the initial bottleneck and during the generations following the bottleneck when the population size is small

Reason:

A population that has experienced may have low genetic diversity even after it recovers its numbers. However, once the number of individuals in it is sufficiently large, it won't be highly susceptible to genetic drift (genetic drift only depends on population size).

Fill in the blank question.

Sometimes populations become susceptible to genetic drift via the ____ effect. This happens when a small group of individuals separates from a larger population and migrates to a different site, where it establishes a colony.

founder

Select all that apply

Choose the two most important results of the founder effect on the newly founded population.

Multiple select question.

The founding population typically has very different allele frequencies from those of the original population.

All allele frequencies in the founding population are very small (close to zero).

The founding population typically has less genetic diversity than the original population.

The founding populations usually has a higher rate of mutation (many new alleles appear).

The founding population typically has very different allele frequencies from those of the original population.

The founding population typically has less genetic diversity than the original population.

Fill in the blank question.

The ____ effect is observed when a population's size is dramatically reduced due to natural events, such as earthquakes and flood, or due to human destruction of habitat.

bottleneck

The human population known as the Old Order Amish of Lancaster County exhibits an unusually high frequency of the genetic disease Ellis-van Creveld syndrome. What explains that observation?

Multiple choice question.

This population recently underwent a genetic bottleneck.

This population was founded by a very small group of people.

This population was founded by a large group of individuals from an original population where this disease was very common.

This population was founded by a very small group of people.

Reason:

The founder effect occurs when a small group of individuals separates from a larger population.

A scientist is studying two populations of the same species of birds - one in Michigan and one in Montana. Both populations are relatively large (with more than 10,000 individuals each). However, the Michigan population has a much lower genetic diversity than the Montana population. Which of the two populations is most likely to have experienced a bottleneck and which of the two populations is currently more susceptible to genetic drift?

Multiple choice question.

The Montana population likely experienced a bottleneck in the past and it is also more susceptible to genetic drift.

The Michigan population likely experienced a bottleneck in the past and is currently more susceptible to genetic drift.

The Michigan population likely experienced a bottleneck in the past. Both populations are equally susceptible to genetic drift.

The Montana population likely experienced a bottleneck in the past. The Michigan population is currently more susceptible to genetic drift.

The Michigan population likely experienced a bottleneck in the past. Both populations are equally susceptible to genetic drift.

Reason:

Due to large population sizes, both populations are equally susceptible to genetic drift.

When individuals migrate, alleles can be transfered from one population to another population. This commonly referred to as

gene flow

A group of individuals from a larger population can migrate to a new area and establish a colony, which will be highly susceptible to genetic drift. This is known as the ______ effect.

Multiple choice question.

colony

founder

island

bottleneck

founder

Fill in the blank question.

When observing the effects of migration, a conglomerate population is formed and is composed of members of both the ____ and ____ populations.

Blank 1: donor

Blank 2: recipient

A founding population usually has lower genetic diversity than the original population it came from. For those alleles that are shared by the two populations, how are allele frequencies different (or similar)?

Multiple choice question.

Usually, the allele frequencies in the founding population are very different from those of the original population.

Usually, the allele frequencies of the founding and the original population are the same.

Usually, the allele frequencies of the founding population are much lower than those of the original population.

Usually, the allele frequencies in the founding population are very different from those of the original population.

Reason:

The frequencies differ but can be either higher or lower in the founding population.

You are studying migration of individuals from a donor population to a recipient population. The frequency of the allele R is 0.6 in the donor population, and 0.8 in the recipient population. The recipient population contained 120 individuals, and 40 individuals migrated into it from the donor population. What will the change in frequency of R be in the conglomerate population after the migration event?

Multiple choice question.

-0.05

0.2

0.5

0.85

-0.05

Reason:

ΔP_c= 0.25(0.6-0.8)

The Old Order Amish of Lancaster County, Pennsylvania were founded by only three couples in the 1700. Currently, this human population is made of thousands of people. Which of the following is a characteristic of this population nowadays, that is a consequence of the founder effect in this population's history?

Multiple choice question.

A much higher frequency of certain very rare human genetic diseases

A higher number of children per couple than in other human populations living in the area

A higher frequency of males than females in the population

A much higher frequency of certain very rare human genetic diseases

Reason:

The number of children will not be specifically related to the founder effect.

You are studying two areas inhabited by a species of frog. In area X, ponds inhabited by the frogs are less frequent and frogs rarely move from one pond to another. In area Z, ponds inhabited by these frogs are connected by a man made system of channels, which allows free movement of frogs between ponds. Which of the following accurately describes differences in allele frequencies between different ponds within each area?

Multiple choice question.

Each pond in area Z should have different allele frequencies, while the allele frequencies in all ponds in area X are likely to be very similar.

In both areas, ponds are likely to have very similar allele frequencies.

Each pond in area X should have different allele frequencies, while the allele frequencies in all ponds in area Z are likely to be very similar.

Each pond in area X should have different allele frequencies, while the allele frequencies in all ponds in area Z are likely to be very similar.

Reason:

The area which allows movement will have similar allele frequencies in all ponds.

For random mating to occur, individuals must choose their mates irrespective of their genotype/phenotype. When this condition is violated, non-random mating is occurring, also known as ____ mating.

assortative

Select all that apply

Which are required for gene flow to occur?

Multiple select question.

Migrants must be fertile and pass their genes to the next generation.

Migrants must have reproduced at least once in the donor population.

Individuals must migrate from one population to another.

At least some of the migrants must be female.

Migrants must be fertile and pass their genes to the next generation.

Individuals must migrate from one population to another.

After migration, the population that has new members due to migration is called the ______ population.

Multiple choice question.

conglomerate

original donor

original recipient

conglomerate

Select all that apply

Consider two populations of the same species and a gene that is found in two alleles in both populations (alleles D and d). Choose all values that need to be known in order to calculate the change in the frequency of the allele D if some individuals migrate from one of the populations into the other.

Multiple select question.

Proportion of the conglomerate population that is due to migrants from the donor population

Frequency of D in the donor population

Frequency of D in the original recipient population

Number of individuals in the donor population before migration occurred

Proportion of the conglomerate population that is due to migrants from the donor population

Frequency of D in the donor population

Frequency of D in the original recipient population

Select all that apply

Inbreeding and outbreeding can cause certain features of populations to deviate from Hardy-Weinberg equilibrium. From the list below, choose the statements that describe commonalities between inbreeding and outbreeding. Assume that no other evolutionary processes are acting on the genes in question.

Multiple select question.

Both inbreeding and outbreeding can quickly change the frequency of certain alleles in the population.

Neither inbreeding or outbreeding affect the relative proportions of different genotypes in the population.

Neither inbreeding or outbreeding affect the allele frequencies in a population.

Both inbreeding and outbreeding alter the relative proportions of heterozygotes in a population.

Neither inbreeding or outbreeding affect the allele frequencies in a population.

Both inbreeding and outbreeding alter the relative proportions of heterozygotes in a population.

In a natural setting, migration between two populations usually occurs in a bidirectional manner (some individuals of each population migrate to the other population). What is the consequence of such bi-directional movement on allele frequencies in the two populations?

Multiple choice question.

Differences in allele frequencies are maintained at a constant level.

Differences in allele frequencies become more pronounced.

Differences in allele frequencies are reduced.

Differences in allele frequencies are reduced.

Reason:

Differences in allele frequencies become more pronounced.

This would occur with migration in only one direction.

Fill in the blank question.

Sometimes, both alleles of a gene in a particular individual are identical because they were actually inherited by descent from the same common ancestor. The probability of that occurring is called the ____ coefficient.

inbreeding

In ____ assortative mating, individuals tend to choose mates with with similar phenotypes. In ____ assortative mating, individuals tend to choose mates with dissimilar phenotypes.

Blank 1: positive or +

Blank 2: negative or -

Based on a pedigree, we can determine all of the inbreeding paths for an individual of interest. The inbreeding paths can then be used to calculate the ______.

Multiple choice question.

heterozygote frequency deviation

homozygote percentage

inbreeding coefficient

inbreeding coefficient

When individuals migrate, alleles can be transfered from one population to another population. This commonly referred to as

gene flow

If an individual has an inbreeding coefficient of 7%, it means that ______.

Multiple choice question.

the probability that a gene in this individual is homozygous due to inheritance from a common ancestor is 3.5%

this individual has a 7% deviation from the Hardy-Weinberg predicted frequency of heterozygous genes

the probability that a gene in this individual is homozygous due to inheritance from a common ancestor is 7%

the proportion of homozygous genes in this individual is 7%

the probability that a gene in this individual is homozygous due to inheritance from a common ancestor is 7%

Reason:

The inbreeding coefficient shows the probability that a gene is homozygous due to inheritance from a common ancestor.

The letter f is used in population genetics to denote how much genotype frequencies deviate from Hardy-Weinberg equilibrium due to non-random mating. If a population has a value of f = -0.5, what type of non-random mating process is occurring and what is its effect on heterozygote frequencies?

Multiple choice question.

Inbreeding; heterozygote frequencies will be lower than predicted by Hardy-Weinberg

Outbreeding; heterozygote frequencies will be lower than predicted by Hardy-Weinberg

Inbreeding; heterozygote frequencies will be higher than predicted by Hardy-Weinberg

Outbreeding; heterozygote frequencies will be higher than predicted by Hardy-Weinberg

Outbreeding; heterozygote frequencies will be higher than predicted by Hardy-Weinberg

Reason:

In natural populations, the value of f tends to become larger as a population becomes smaller, because each individual has a more limited choice in mate selection.

Fill in the blank question.

When two genetically related individuals mate, it is called ____. In contrast, mating between unrelated individuals is known as ____.

Blank 1: inbreeding

Blank 2: outbreeding

Which of the following is a major disadvantage of inbreeding in natural populations?

Multiple choice question.

Inbreeding lowers the mean fitness of a population when homozygotes have a lower relative fitness value.

Inbreeding prevents natural selection from occurring, as individuals are inheriting two copies of the same allele from a common ancestor.

Inbreeding produces sterile animals that do not contribute their genes to the next generation.

Inbreeding lowers the overall fitness of a population by causing a deviation from the Hardy-Weinberg equilibrium.

Inbreeding lowers the mean fitness of a population when homozygotes have a lower relative fitness value.

Reason:

Inbreeding can change the amount of variation but does not prevent natural selection from occurring.

Reason:

The overall fitness is reduced if the fitness of homozygotes is lower.

Which of the following best defines the inbreeding coefficient?

Multiple choice question.

The percent of matings in a population that are between related individuals.

The probability that two identical alleles in an individual are inherited by descent from the same common ancestor.

The probability that an individual will mate with a related individual in a population.

The probability that two identical alleles in an individual are inherited by descent from the same common ancestor.

Reason:

The inbreeding coefficient determines the likelihood of inheriting identical alleles from the same common ancestor.

How is the inbreeding coefficient of an individual calculated?

Multiple choice question.

Inbreeding coefficients can be calculated by determining inbreeding paths in a pedigree.

Inbreeding coefficients are calculated by dividing the number of inbreeding events in a pedigree by the total number of matings in it.

Inbreeding coefficients are calculated by dividing the number of individuals produced by inbreeding by the total number of individuals in a pedigree.

Inbreeding coefficients can be calculated by determining inbreeding paths in a pedigree.

Reason:

This coefficient is calculated by determining inbreeding paths in a pedigree.

Sometimes, a population can experience high levels of inbreeding if the population's size has been reduced for some reason. This can lead to lower reproductive success, causing an even larger decrease in the population's size, a phenomenon known as inbreeding

depression

Consider an individual that has an inbreeding coefficient of 4%. What is the probability that this individual is homozygous dominant for the the cystic fibrosis gene because he inherited the same allele twice from a common ancestor (due to inbreeding)?

Multiple choice question.

8%

2%

96%

4%

2%

Reason:

A 4% inbreeding coefficient means that there is 4% chance that a gene is homozygous (could be dominant or recessive) due to inheritance from the same ancestor. Since each gene in eukaryotes is represented by two alleles, the probability that the individual is homozygous dominant is only 2%. Likewise, the probability that the individual is homozygous recessive, is also 2%.

A ____ is any change in the DNA of an organism, for example, a change in DNA sequence or the structure and number of chromosomes.

mutation

Consider a population in which a gene is present in the form of two alleles with the following frequencies: A=0.4, and a=0.6. The value of f (how much genotype frequencies deviate from Hardy-Weinberg equilibrium due to non-random mating) for this population is 0.3. What would the predicted frequency of heterozygotes be in this population?

Multiple choice question.

0.34

0.17

0.24

0.48

0.34

Reason:

Heterozygote frequency can be calculated using the formula 2pq(1-f). Thus, 2(0.4)(0.6)(1-0.3) = 0.34

Most mutations are ______.

Multiple choice question.

deleterious or neutral

neutral or beneficial

beneficial

deleterious or neutral

Reason:

Beneficial mutations that provide a selective advantage are relatively rare.

Why is inbreeding useful in agriculture?

Multiple choice question.

It can result in a high proportion of heterozygotes, which typically exhibit the traits that are of interest to breeders.

It can result in a high proportion of homozygotes that exhibit a trait that is of interest to a breeder.

It can result in a high proportion of heterozygotes, which are typically more resistant to diseases.

It can result in a high proportion of homozygotes, which can help eliminate certain genetic diseases.

It can result in a high proportion of homozygotes that exhibit a trait that is of interest to a breeder.

Reason:

Inbreeding increases the likelihood that an individual will become homozygous recessive for a trait.

Which of the following is a typical mutation rate (with proper units) for a gene in a natural population?

Multiple choice question.

10⁶ per gene per generation

10⁶ per individual per population

10^-6 per gene per generation

10^-6 per individual per generation

10^-6 per gene per generation

Consider a gene which is found in two forms in a population: D and d, with frequencies of 0.6 and 0.4, respectively. The D allele can mutate into the d allele at a rate of 0.00001 mutations per gene per generation. What would the expected frequency of the d allele be after one generation (assume that the reverse mutation d to D does not occur)?

Multiple choice question.

0.36662

0.399994

0.50000

0.400006

0.400666

0.400006

Reason:

Δp=(0.00001 x 0.6)=0.000006, which is added to the value for q.

Click and drag on elements in order

Order the events that a population undergoing inbreeding depression might experience, starting at the top.

The mean fitness of the population decreases, which leads to a decrease in its reproductive success.

The population experiences high level of inbreeding due to its small size.

The population size decreases even more, possibly leading to extinction.

Population size is dramatically reduced by habitat destruction.

1. Population size is dramatically reduced
2. Population experiences high level of inbreeding
3. Mean fitness decreases
4. Population decreases even more, possible extinction

How is a protein domain related to the exons of a gene?

Multiple choice question.

Each protein domain tends to be encoded by a single exon, or in some cases a few, adjacent exons.

Each protein domain studied so far is encoded by a single exon in the gene.

Each protein domain can be encoded by any number of exons that do not have to be adjacent.

Each protein domain tends to be encoded by a single exon, or in some cases a few, adjacent exons.

Fill in the blank question.

Mutations occur when the DNA of an organism changes. Changes often happen in gene ____, but may also involve the structure and number of chromosomes.

sequences

A new allele can arise when an exon and its flanking introns are inserted into another gene. The new allele produces a protein which now has an additional domain (encoded by the inserted exon). This mechanism of new allele formation is known as exon

shuffling

New mutations can be deleterious, neutral, or beneficial. Which of those three general types of mutations are most likely to occur?

Multiple choice question.

Beneficial mutations are much more likely than neutral or deleterious mutations.

Deleterious and neutral mutations are much more likely than beneficial mutations.

Neutral mutations are much more likely than deleterious and beneficial mutations.

Deleterious mutations are much more likely than neutral and beneficial mutations.

Deleterious and neutral mutations are much more likely than beneficial mutations.

Reason:

Both deleterious and neutral mutations are more likely than beneficial ones.

The probability that a gene will be altered as a result of mutation is known as the mutation

rate

Fill in the blank question.

One way in which exon shuffling can occur is by ____ elements, which can insert exons from one gene into the sequence of another gene.

transposable

Consider a gene which is found in two forms in a population: B and b, each with a frequency of 0.5. The B allele can mutate into the b allele at a rate of 0.0001 mutations per gene per generation. What would the expected frequency of the B allele be after 100 generations (assume that the reverse mutation b to B does not occur)?

Multiple choice question.

0.495

0.5005

0.45992

0.49992

0.495

Reason:

Solve the equation: (1-0.0001)¹⁰⁰=p_t/0.5

The transfer of genetic material from one species to another (regardless of the exact mechanism) is called ______.

Multiple choice question.

vertical gene transfer

gene shuffling

horizontal gene transfer

nonhomologous recombination

horizontal gene transfer

By looking at many different proteins and the genes that encode them in a variety of eukaryotic organisms, scientists have determined that a protein domain tends to be encoded by one or a few (usually adjacent)

exons

What is the result of exon shuffling?

Multiple choice question.

A novel gene that may encode a protein with a novel combination of functional domains.

A second copy of a gene that can mutate and produce a new type of protein domain.

The same gene can be used to produce two or more proteins.

A novel gene that may encode a protein with a novel combination of functional domains.

Reason:

Exon shuffling involves the reorganization of existing protein domains.

Reason:

This is achieved through alternative splicing.

True or false: While horizontal gene transfer is very common between different species of bacteria, it cannot occur between different species of eukaryotes, or between eukaryotes and bacteria.

False

Reason:

Horizontal gene transfer occurs in all organisms.

What type of recombination event can result in exon shuffling?

Multiple choice question.

A homologous recombination

Any crossover event

A nonhomologous recombination

A nonhomologous recombination

Fill in the blank question.

During ____ gene transfer, genetic material from a donor organism is incorporated into a recipient organism which is not the donor's offspring.

horizontal

Repetitive sequences are composed of a certain sequence that is repeated many times throughout the genome of a species. What is the typical size of the sequence that is being repeated?

Multiple choice question.

A few to a few thousand base pairs

A few base pairs (never more than 10)

A few to a few hundred thousand base pairs

Ten to a hundred base pairs

A few to a few thousand base pairs

Reason:

A few hundred thousand base pairs is too large for a repetitive sequence.

A short tandem repeat (STR), or ______, is a type of repetitive sequence which is less than two hundred base pairs in length and for which the unit that repeats is about 1-6 bp long. In contrast, ______ are 1-20 kbp long and are composed of a unit that is 6-80 base pairs long.

Multiple choice question.

microsatellite; minisatellites

minisatellite; microatellites

microsatellite; minisatellites

Horizontal gene transfer (HGT) between different species of bacteria is relatively common. Scientists estimate that about ______ of the genetic variation between modern bacteria can be attributed to HGT.

Multiple choice question.

20-30%

5%

80-90%

20-30%

Reason:

Scientists estimate that about 20-30% of the genetic variation between modern bacteria can be attributed to HGT.

How can micro and minisatellites be used to determine the relatedness between individuals within a population?

Multiple choice question.

The sizes of those repetitive sequences tend to be more similar in closely related individuals.

Individuals that are not closely related usually do not have the same types of micro and minisatellites.

While their sizes are relatively constant, micro and minisatellites tend to have different sequences in less related individuals.

The sizes of those repetitive sequences tend to be more similar in closely related individuals.

Reason:

Micro and minisattelites tend to change in size, where the number of tandem repeats changes.

Most eukaryotic species contain short sequences, typically a few base pairs to a few thousand base pairs long, that are repeated many times throughout the genome. Using a general term, these are called ______ sequences.

Multiple choice question.

repetitive

satellite

short repeated

fingerprint

repetitive

Which of the following is a similarity between microsatellites and minisatellites?

Multiple choice question.

They are never more than 200 hundred base pairs long.

They are usually between 1,000 and 20,000 base pairs long.

They consist of many tandem repeats of a certain DNA sequence.

They are mobile DNA elements.

They consist of many tandem repeats of a certain DNA sequence.

Fill in the blank question.

In DNA ____, an individual is characterized based on the repetitive sequences in his or her genome.

fingerprinting

How can DNA fingerprinting be used to determine if a natural population is undergoing inbreeding depression?

Multiple choice question.

DNA fingerprinting can be used to precisely determine each individual's parents.

DNA fingerprints can show when mutations have appeared in the population and if they are strongly influenced by genetic drift.

DNA fingerprints can be used to determine the degree of relatedness between the population's members.

DNA fingerprints can be used to determine the degree of relatedness between the population's members.

Reason:

The degree of relatedness among members of a population is used to determine if an inbreeding depression has occurred.

Why are repetitive sequences, such as micro and minisatellites an extremely useful tool for studying population genetics?

Multiple choice question.

Because mutations in those elements are always neutral or beneficial

Because they are found in all individuals of a population

Because they tend to exhibit considerable variation between individuals

Because they tend to exhibit considerable variation between individuals

Which technique characterizes human individuals by analyzing the presence and sizes of repetitive sequences in their DNA?

Multiple choice question.

STR fingerprinting

DNA fingerprinting

DNA identification

Microsatellite profiling

DNA fingerprinting

DNA fingerprinting can be used to determine the relationship between humans (for example paternity) because closely related individuals, such as a father and his child ______.

Multiple choice question.

have more variable DNA fingerprints than do more distantly related individuals

always have identical DNA fingerprints

have more similar DNA fingerprints than do more distantly related individuals

have more similar DNA fingerprints than do more distantly related individuals