Deck 16: The Genetics of Populations

Question 1

Which of the following processes affects genotype frequencies without affecting allele frequencies?

A) Genetic drift
B) Migration
C) Mutation
D) Non-random mating

Answer 1

Non-random mating

Question 2

Fill in the blank. A group of organisms in a specific place and time that is capable of genetic exchange is termed an _______ population

Answer 2

effective

Question 3

Match the missing words in the following phrase. The [A] describes how often a particular DNA sequence is found in a [B]. The collection of all [C] present in a population is termed the [D]. [E] are variants that occur in a population at a [F] > 0.01.

Answer 3

a. A = allele frequency
b. B = population
c. C = alleles
d. D = gene pool
e. E = polymorphic loci
f. F = frequency

Question 4

An experimental population contains a dominant allele T with frequency 0.65. What is the frequency of the recessive allele t? Assume that there are only two alleles for this locus.

Question 5

In a population of 1000 people, 90 have red hair, 57 have brown hair, 521 have blond hair, and 332 have black hair. In this example population, the red hair allele, r, is recessive to alleles for black, brown, and blond hair. What is the frequency of the red hair allele in this population?

Question 6

Which of the following are true for a population that is in Hardy-Weinberg equilibrium? Please select all that apply.

A) Mating is random
B) Any allele can unite with any other allele
C) Allele frequency changes between generations
D) Genotype frequency can be inferred from allele frequency
E) Selection forces are acting on the population

Question 7

Positive assortative mating increases the proportion of heterozygotes in a population.

Question 8

Which of the following terms is used to describe alleles that share the same variants and haplotype and are found in closely related individuals?

A) Consanguinity
B) Inbred
C) Recessive
D) Identical by descent

Question 9

Which of the following has the least impact on allele frequencies in a population?

A) Mutation
B) Genetic drift
C) Migration
D) Selection

Question 10

Which of the following statements about reproductive migration between populations is untrue?

A) Cultural differences between populations are a barrier to migration
B) When migration is prevented, separate species can arise
C) Geographic distance can produce reproductively isolated populations
D) Migration decreases homogeneity in the overall population

Question 11

The Icelandic population is of European descent, yet is very homogenous and carries some common polymorphisms that are rare in Europe. What factors have led to the difference between the Icelandic and European populations? Please select all that apply.

A) Genetic drift
B) Migration
C) Founder effect
D) Population bottleneck

Question 12

Compared to other populations, Tay Sachs disease is relatively common in the French Canadian and Jewish populations. Which of the following statements are true about two different populations that have an elevated incidence of the same genetic disease?
Please select all that apply.

A) The increased likelihood of a disease in two different populations suggests that the disease variant in the two populations may be derived from a common ancestor
B) Genetic drift has increased the disease likelihood in the two populations compared to other populations
C) It can be concluded that a common variant is responsible for the disease in the two populations
D) The two populations are actually one population

Question 13

Which of the following is the basis of natural selection?

A) Recessive alleles
B) Mutation
C) Small population size
D) Differential reproductive ability

Question 14

Which of the following terms is used for a trait that allows organisms to better thrive and reproduce in their environment?

A) Dominant trait
B) Fixed trait
C) Directional trait
D) Adaptive trait

Question 15

Which of the following statements are true about 'survival of the fittest' in an evolutionary context? Please select all that apply.

A) The fittest organisms are those that reproduce most successfully
B) The fittest organisms are those that survive the longest
C) The fittest organisms are the same in every generation
D) The fittest individuals are improvements on earlier individuals in the species

Question 16

Which of the following statements about directional selection are true? Please select all that apply.

A) Directional selection is also known as stabilizing selection
B) Phenotype frequency changes between generations with directional selection
C) Allele frequency does not change between generations with directional selection
D) The AA genotype is more advantageous than the aa genotype

Question 17

Which of the following statements about heterozygote advantage are true? Please select all that apply.

A) Heterozygote advantage is a type of purifying selection
B) Alleles do not become fixed with heterozygote advantage
C) The locus under selection is polymorphic
D) The AA genotype is more advantageous than the Aa genotype

Question 18

A group of zoo chimpanzees was analyzed over several years. Which of the chimpanzees was the fittest in this environment?
$$\begin{array} { | l | c | c | c | c | } \hline \text { Name } & \begin{array} { c } \text { Age at } \\\text { death }\end{array} & \begin{array} { c } \text { Weight } \\( \mathrm { kg } )\end{array} & \begin{array} { c } \text { Number of } \\\text { offspring }\end{array} & \begin{array} { c } \text { Number of } \\\text { surviving offspring }\end{array} \\\hline \text { Daisy } & 32 & 38 & 4 & 4 \\\hline \text { Bella } & 55 & 32 & 3 & 3 \\\hline \text { Lucy } & 46 & 43 & 6 & 2 \\\hline \text { Anna } & 28 & 45 & 5 & 2 \\\hline\end{array}$$

A) Anna
B) Lucy
C) Bella
D) Daisy

Question 19

Which type of selection is responsible for the high frequency of the 'sickle cell allele' in some populations?

A) Sexual selection
B) Purifying selection
C) Disruptive selection
D) Balancing selection

Question 20

Match the missing words in the following phrase. Frequency-dependent selection is a type of [A] selection. In [B] selection and heterozygote advantage, selection is [C] other individuals in the population, whereas frequency-dependent selection is [D] other individuals in the population.

Question 21

Using the Jukes-Cantor model, most loci in a genome have a dN/dS ratio < 1. This is because most nonsynonymous mutations are deleterious and are selected against.

Question 22

Which of the following statements about lactase persistence in humans are true? Please select all that apply.

A) Most people do not exhibit lactase persistence
B) Lactase persistence is due to mutations in the lactase gene
C) The mutation rate in the lactase gene is higher in herding populations than in non-herding populations
D) Lactase persistence is a derived condition
E) Lactase persistence is an example of positive selection

Question 23

A haplotype on Chromosome 2 that contains the EDAR gene is found at a frequency of 90% in the Han Chinese population but is essentially absent in other populations. Which of the following pieces of evidence suggested that this haplotype had a recent origin?

A) China was thought to be very hot and humid at the time the haplotype arose
B) The EDAR gene is thought to increase sweating
C) The EDAR gene has pleiotropic effects
D) The haplotype is long

Question 24

Which of the following characteristics demonstrate increased fitness in bacterial populations? Please select all that apply.

A) Reduced generation time
B) Increased generation time
C) Faster growth rate
D) Slower growth rate

Question 25

Disruption of a bacterial DNA repair gene is likely to decrease the rate of evolution.