Deck 22: Population Genetics and Evolution

Question 1

Which aspect of population genetics can lead to changes in allele frequencies in a new mixed population following migration?

A)natural selection
B)mutation
C)gene flow
D)founder effect
E)bottleneck effect

Answer 1

C

Question 2

Which aspect of population genetics refers to chance fluctuations of allele frequencies resulting from sampling error and is more prominent in small, isolated populations?

A)founder effect
B)mutation
C)gene flow
D)gene drift
E)bottleneck effect

Answer 2

D

Question 3

The coefficient of inbreeding (F)can be used to estimate the proportion of loci that are __________.

A)fixed in a population
B)homozygous identical by descent
C)heterozygous by descent
D)lethal alleles
E)recessive

Answer 3

B

Question 4

Phenylketonuria (PKU)is extremely common in Ireland, affecting approximately 1 in 4500 live births. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of PKU carriers?

A)0.022%
B)98.5%
C)2.9%
D)1.49%
E)2.2%

Question 5

All Old Order Amish families from Lancaster County with Ellis-van Creveld syndrome can trace their genealogies to Mr. and Mrs. Samuel King, who immigrated to Lancaster County in 1744. This is an example of __________.

A)founder effect
B)mutation
C)gene flow
D)Hardy-Weinberg equilibrium
E)bottleneck effect

Question 6

Which of the following is an example of a postzygotic mechanism for reproductive isolation?

A)behavioral isolation
B)gametic isolation
C)habitat separation
D)mechanical isolation
E)hybrid sterility

Question 7

If an X-linked recessive trait has a frequency of 5% in males, what percentage of females are carriers? (Assume that the population is in Hardy-Weinberg equilibrium.)

A)9.5%
B)5%
C)95%
D)4.2%
E)10%

Question 8

What type of statistical analysis is used to compare observed and expected results in order to evaluate the validity of an estimate based on the Hardy-Weinberg equilibrium?

Question 9

Given the following pedigree, what is the coefficient of inbreeding for individual IV-1?

A)1/2
B)1/4
C)1/8
D)1/16
E)1/64

Question 10

Physical separation of a segment of a large population by a physical barrier that prevents gene flow can lead to __________.

A)sympatric speciation
B)allopatric speciation
C)hybrid sterility
D)temporal isolation
E)gene flow

Question 11

You want to calculate the frequency of the allele causing sickle cell disease in your patients, and you know the genotypes of every individual. Assuming the population is not in Hardy-Weinberg equilibrium due to population substructure, which method can be used to calculate allele frequency?

A)allele-counting method
B)genotype proportion method
C)square root method
D)binomial expansion
E)chi-square test

Question 12

In a group of 500 people, the frequency of genotype NN is 40%. Assuming both autosomal inheritance and that the population is in Hardy-Weinberg equilibrium, how many individuals would you expect to have the MN genotype?

A)68
B)232
C)300
D)200
E)258

Question 13

Cheetahs exhibit significant inbreeding and loss of heterozygosity due to overhunting and loss of habitat experienced at some point in their evolutionary history. Which genetic mechanism occurs when a large population is substantially reduced at random, acting independently of natural selection?

A)founder effect
B)mutation
C)gene flow
D)Hardy-Weinberg equilibrium
E)bottleneck effect

Question 14

Given the following genetic profile, what is the mean fitness of the population? Genotype A₁A₁ A₁A₂ A₂A₂
Frequency 0.55 0.20 0.25
Number 2750 1000 1250
Relative fitness (w)1.0 0.75 0.50

A)1
B)0.75
C)0.825
D)0.3025
E)0.55

Question 15

Mexican hairless dogs are heterozygous (Hh), carrying a single copy of the recessive lethal allele. In a given population, the Hh genotypic frequency is 60% and the frequency of each homozygote
Is 20%. Assuming w = 1 for the Hh and hh dogs, what is the estimated genotypic frequency of the lethal HH genotype after reproduction?

A)20%
B)14%
C)10%
D)39%
E)46%

Question 16

In CODIS, what type of genetic marker is used to predict population genotype frequencies?

A)dsRNAs
B)PCR products
C)CpG islands
D)STRPs
E)FISH chromosome patterns

Question 17

When populations share a single habitat but are isolated by genetic or postzygotic mechanisms that prevent gene flow, what process can cause populations to diverge?

A)random mating
B)allopatric speciation
C)sympatric speciation
D)random mutation
E)gene duplication

Question 18

In the same population of patients you examined for sickle cell allele frequencies, you now want to test whether the disease symptoms are related to blood type. Since blood type is a codominant trait and the alleles are easily identifiable by the phenotype (blood type)of the individuals, which method is most helpful for identifying blood type allele frequency?

A)allele-counting method
B)genotype proportion method
C)square root method
D)binomial expansion
E)chi-square test

Question 19

Both the founder effect and the bottleneck effect are mechanisms that produce large allele frequency sampling errors in a small population due to __________.

A)random mutation
B)gene flow
C)gene drift
D)lethal alleles
E)random mating

Question 20

The process by which an original species is transformed into a new species over an extended period of time that spans many generations is known as __________.

A)anagenesis
B)cladogenesis
C)morphogenesis
D)neogenesis
E)founder effect

Question 21

Of the five aspects of Hardy-Weinberg equilibrium, which one directly affects phenotypic frequencies for both rather than genotypic frequencies?

Question 22

Using the allele frequencies in the table below, what is the probability that a random person would be heterozygous 12/14 for VAW?

Question 23

When examining the effects of forward and reverse mutation rates, what equation is used to calculate the change in the frequency of A₂, or Δq?

Question 24

In a theoretical population where f (A₁)= 0.95 and f (A₂)= 0.05, µ = 1 × 10^-6, and v = 1 × 10^-7, what is Δq?

Question 25

Inbreeding depression, the reduction in fitness of inbred organisms, often results from the reduced level of what (within the gene pool)?

Question 26

If the genotype frequency in an admixed population is f (A₁)= 0.75, what is the genotypic frequency of heterozygotes in the admixed population?

Question 27

If the frequency of PKU (an autosomal recessive disease)is 1%, what percentage of the population are completely unaffected (homozygous dominant or carrier)?

Question 28

If the relative fitness value is w = 0.6, what is the selection coefficient used to identify the differences between the fitnesses of organisms with different traits?

Question 29

Using the allele frequencies in the table below, what is the probability that a random person who was heterozygous 12/14 for VAW would also be homozygous 18/18 for FAG? (Assume that the two loci are unlinked.)

Question 30

If the frequency of PKU, an autosomal recessive disease, is 1% in males, what is the frequency of females with PKU? (You may assume that the population is in Hardy-Weinberg equilibrium.)

Question 31

If the frequency of hemophilia, an X-linked recessive disease, is 10% in males, what is the frequency of carriers in the population (both males and females)?

Question 32

What is the ultimate source of genetic variation in populations?

Question 33

When looking at the MN blood group with three alleles, how many degrees of freedom will be used to compare observed versus expected results?

Question 34

A difference in allelic frequencies that is produced when a new population is established by a few individuals is known as what type of genetic drift?

Question 35

Which mechanism maintains the biological ability of populations to interbreed and can thus prevent evolutionary divergence of populations?

Question 36

What are the two most common types of nonrandom mating?

Question 37

________ is an evolutionary mechanism that favors the reproductive success of certain members of a population over others as a result of differences in anatomical, physiological, or behavioral traits they possess.

Question 38

If the frequency of hemophilia, an X-linked recessive disease, is 10% in males, what is the frequency of females with hemophilia (assuming that the population is in Hardy-Weinberg equilibrium)?

Question 39

If the heterozygous genotype is favored (as exhibited by the sickle cell allele in malaria-prone regions), selection results in a ________ in which alleles reach stable equilibrium frequencies that are maintained by the ongoing action of selection against the homozygous genotypes.

Question 40

Which two molecular techniques are used in DNA profiling to generate data included in the FBI's CODIS database?

Question 41

The coefficient of inbreeding quantifies the probability that two alleles in a homozygous individual are ________, having descended from the same copy of the allele carried by a common ancestor of the inbred individual.

Question 42

In the general population, 1 in 300 individuals is a carrier for Tay-Sachs disease, while 1 in 30 individuals of Ashkenazi Jew descent are carriers. Tay-Sachs also affects 1 in 30 individuals with French-Canadian ancestry, although two completely unique mutations are responsible for the Ashkenazi and French-Canadian mutations. What are the chances of two individuals who are carriers having a child with Tay-Sachs if
a. both individuals are not of Ashkenazi or French-Canadian descent?
b. one individual is of Ashkenazi descent and one is not?
c. both individuals are of Ashkenazi descent?

Question 43

The pattern of species evolution known as ________ is one of branching in which an ancestral species gives rise to two or more new species.

Question 44

Forward and reverse mutation can create a ________, given a sufficient number of generations and the absence of other evolutionary processes.

Question 45

What are the three key elements for determining F, a measure that a particular allele is IBD, using pedigree analysis?

Question 46

Explain why rare recessive alleles are more likely to produce a recessive phenotype as a result of inbreeding.

Question 47

In an island population, the frequencies of the three MN blood types are given here:
M: 550
MN: 725
N: 225
a. Calculate the allele frequency of M and N.
b. Assuming random mating, what are the expected frequencies for each blood type?
c. Use chi-square analysis to test your hypothesis that mating is random for this population.