Deck 23: Population Genetics

Question 1

In a given population of Drosophila,curly wings (c )is recessive to the wild-type condition of straight wings (c⁺ ).You isolate a population of 35 curly winged flies,70 flies that are heterozygous for straight wings,and 45 that are homozygous for straight wings.What is the total number of alleles in the gene pool?

A) 2
B) 150
C) 230
D) 300
E) None of these choices are correct

Answer 1

D

Question 2

Given the allele frequency for a gene in population A is 0.3 and the frequency for the same allele in population B is 0.5 and that 25 individuals from A migrate to and mate randomly with the 475 individuals in population B,what is the new allele frequency (PC)in the conglomerate?

A) 0.052
B) 0.2
C) 0.8
D) 0.49

Answer 2

D

Question 3

Most natural populations are in Hardy-Weinberg equilibrium.

Answer 3

False

Question 4

Which of the following types of selection creates two phenotypic classes from a single original distribution?

A) disruptive selection
B) stabilizing selection
C) directional selection
D) balancing selection

Question 5

Which of the following is NOT an assumption of the Hardy-Weinberg equation?

A) There is no migration into or out of the population.
B) Individuals of the population mate randomly.
C) The population size is very large.
D) Selection favors the dominant allele.
E) There is no mutation occurring in the population.

Question 6

A SNP would best be described as 

A) a gene that comes in multiple different alleles.
B) a balanced polymorphism system.
C) a single nucleotide difference between two DNA sequences.
D) the least frequent type of mutation.
E) None of these choices are correct.

Question 7

Which type of selection would lead to two distinct phenotypes?

A) stabilizing selection
B) phenotype selection
C) fitness selection
D) disruptive selection
E) directional selection

Question 8

The term for the mating for two genetically unrelated individuals is

A) outbreeding.
B) inbreeding.
C) disassortative mating.
D) assertive mating.

Question 9

Which of the following types of selection is typically associated with quantitative traits?

A) disruptive selection only
B) both stabilizing and disruptive selection
C) stabilizing selection only
D) balancing selection

Question 10

Which of the following types of selection favors one extreme of a phenotypic distribution?

A) disruptive selection
B) stabilizing selection
C) directional selection
D) balancing selection

Question 11

In the equation p² + 2pq + q² = 1,what does the term 2pq represent?

A) the genotypic frequency of homozygous recessive individuals
B) the genotypic frequency of homozygous dominant individuals
C) the genotypic frequency of heterozygous individuals
D) the sum of the phenotypic frequencies in the population
E) None of these choices are correct.

Question 12

Natural selection occurs when

A) individuals whose phenotypes are best suited for environmental conditions have higher reproductive success and contribute more alleles to the next generation.
B) humans breed certain individuals with the most desirable phenotypes.
C) individuals whose phenotypes are best suited for environmental conditions have lower reproductive success but live longer.
D) the genotype of an individual does not determine whether or not is has reproductive success.

Question 13

If a gene has more than one allele and each allele has a frequency that is less than 99%,then the gene is considered to be 

A) monomorphic.
B) polymorphic.
C) bialleleic.
D) polyallelic.

Question 14

In a given population of Drosophila,curly wings (c )is recessive to the wild-type condition of straight wings (c⁺ ).You isolate a population of 35 curly winged flies,70 flies that are heterozygous for straight wings,and 45 that are homozygous for straight wings.What is the frequency of alleles in this population?

A) 35% c; 45% c⁺
B) 46.7% c; 53.3% c⁺
C) 50% c; 50% c⁺
D) 55% c; 45% c⁺
E) None of these choices are correct.

Question 15

Migration of a random few individuals from one population to a new area to establish a new population is an example of 

A) bottleneck effect.
B) mutation.
C) founder effect.
D) selection.

Question 16

A natural disaster that resulted in the loss of genetic diversity in a population would be an example of a

A) founder effect.
B) genetic drift.
C) bottleneck effect.
D) natural selection.

Question 17

Genetic drift has the greatest influence on allele frequencies for which population size?

A) small
B) large
C) Genetic drift has the same impact on both large and small populations.
D) Genetic drift has no effect on the allele frequencies.

Question 18

The probability that two alleles will be identical for a given gene in an individual because the alleles are from the same ancestor is estimated by

A) the calculation of average heterozygosity.
B) the Hardy-Weinberg equation.
C) the inbreeding coefficient.
D) the chi-square test.

Question 19

The formula p² + 2pq + q² = 1 is associated with which of the following?

A) calculations of heterozygosity
B) Hardy-Weinberg equilibrium
C) calculations of recombination frequencies
D) degrees of freedom
E) None of these choices are correct.

Question 20

The term for a group of individuals from the same species that can interbreed with one another is 

A) species.
B) population.
C) race.
D) community.
E) kingdom.

Question 21

If the allele frequency of the dominant allele is 0.4,what value is used for the term p² in the equation p² + 2pq + q² = 1?

A) 0.4
B) 0.2
C) 0.16
D) 16

Question 22

How does inbreeding affect the Hardy-Weinberg equilibrium?

A) It makes it more likely for the population to remain in Hardy-Weinberg equilibrium.
B) It has no effect on the Hardy-Weinberg equilibrium.
C) It results in a higher level of either dominant or recessive homozygotes.
D) It results in a higher level of heterozygotes.

Question 23

If in a population the rate of mutation that converts the A allele to the a allele is 10⁻⁶ and the current frequency of the A allele is 0.75 and the a allele is 0.25,then the frequency of the A and a alleles in the next generation will be

A) A: 0.75
A: 0.25
B) A: 0.7499993
A: 0.2500007
C) A: 0.750007
A: 0.2499993
D) A: 0.74
A: 0.26

Question 24

The mechanism that results in a change in allele frequencies due to random processes is known as

A) genetic drift.
B) natural selection.
C) migration.
D) nonrandom mating.

Question 25

Microevolution is defined as

A) changes in the gene pool from one generation to the next.
B) changes in gene flow from one generation to the next.
C) the ability of different genotypes to succeed in a particular environment.
D) morphological changes that occur from one generation to the next.

Question 26

Horizontal gene transfer occurs

A) within and between species of eukaryotes and prokaryotes.
B) between prokaryotic species only.
C) between eukaryotic species only.
D) only from prokaryotes to eukaryotes.

Question 27

Consider a hypothetical gene B for which there are two alleles in the population.For every ten BB individuals that survive,six Bb individuals survive,and one bb individual survives.What are the relative fitness values for each genotype?

A) wBB = 1.0; wBb = 0.6; wbb = 0.1
B) wBB = 100; wBb = 0.6; wbb = 0.01
C) wBB = 0.59; wBb = 0.35; wbb = 1.0
D) wB = 26; wb = 7

Question 28

A population with an allele for a gene that constitutes 99% of the alleles in the population means that the population is called monomorphic for that gene.

Question 29

Repetitive sequences are useful for DNA fingerprinting because they

A) are not inherited and so are unique to every individual.
B) are unique to every individual and change from generation to generation.
C) are inherited and can show significant variability between individuals.
D) never undergo mutation.

Question 30

You are preparing to perform DNA fingerprinting by PCR for the first time.Select the reagent that would result in complications in the interpretation of your results.

A) PCR primers that anneal to the repetitive region of the microsatellites
B) PCR primers that anneal to regions flanking the microsatellites
C) Human DNA
D) Taq polymerase

Question 31

At equilibrium the allelic and genotypic frequencies of a population change over time.

Question 32

Which term describes all the alleles of every gene in the population?

A) conglomerate
B) gene pool
C) polymorphisms
D) genotype frequency

Question 33

The probability that a gene will be altered by a mutation is called the mutation rate.

Question 34

Select the definition of genetic drift.

A) Changes in allele frequencies in a population due to random fluctuations
B) Changes in allele frequencies in a population due to migration
C) Changes in genotype frequencies in a population due to new mutations
D) Changes in genome size in a species due to random mutations

Question 35

Mutations represent

A) a minor part of microevolution.
B) an essential part of microevolution.
C) deleterious changes to the fitness of an individual.
D) advantageous changes to genes.

Question 36

The prevalence of the allele for sickle cell anemia in some populations is an example of which of the following?

A) heterogeneous environments
B) balancing selection
C) inverted selection
D) non-Darwinian selection
E) nonrandom mating

Question 37

If two individuals of a population,who vary in their phenotype,preferentially mate,it is called ________.

A) Outbreeding
B) Inbreeding
C) Negative assortative mating
D) Positive assortative mating

Question 38

Calculate the inbreeding coefficient of an individual given an n of 4 (excluding the inbred offspring)with one common ancestor. The inbreeding of the common ancestor is unknown.

A) 25%
B) 3.125%
C) 6.25%
D) 50%

Question 39

Which of the following is NOT an assumption of the Hardy-Weinberg equation?

A) The population is large.
B) There is no migration into or out of the population.
C) There is no selection against a given genotype.
D) There is no mutation in the gene being studied.
E) There is nonrandom mating.