Question 1

Briefly describe the structure of compound chromosomes,and explain how their behavior during meiosis can be used to study underdominance.

Accepted Answer

Compound chromosomes are homologous chromosomes that have exchanged entire arms; one homolog therefore contains two copies of one arm,whereas the other homolog contains two copies of the other arm.During meiosis,four types of gametes are produced in equal numbers; gametes with both homologous chromosomes,gametes with just one member of the pair,gametes with the other member of the pair,or gametes containing no members of the homologous pair.Heterozygotes produced are therefore not viable,so the resultant populations consist of only homozygotes.

Question 2

The probability that two mutually exclusive events will occur is calculated by ________.

Accepted Answer

A)   multiplying the probability of each individual event
B)   adding the probability of each individual event
C)   adding the probability of each individual event and subtracting 1
D)   adding the probability of each individual event and multiplying by 2 B

Question 3

Cavener and Clegg (1981)demonstrated natural selection by observing the cumulative change in allele frequencies in populations of Drosophila melanogaster that were subjected to high levels of ________.

Accepted Answer

A)   mercury
B)   carbon dioxide
C)   alcohol
D)   sugar
E)   nitrous oxide C

Question 4

In the study of Gigord and colleagues using Elderflower orchids,the allele frequencies of yellow and purple flowers varied such that when the yellow allele started to become rare,the reproductive success of purple flowers decreased and the reproductive success of yellow-flowered individuals increased in a process known as ________.

Accepted Answer

A)   overdominance
B)   frequency-dependent selection
C)   underdominance
D)   Hardy-Weinberg stabilization
E)   frequency depression

Question 5

If a population is in Hardy-Weinberg equilibrium,which of the following statements is correct?

Accepted Answer

A)   Each allele will be present at a 50% frequency.
B)   Allele frequencies can vary from generation to generation, but the average frequency must remain constant.
C)   The size of the population must remain constant from generation to generation.
D)   Allele frequencies must remain the same from generation to generation.
E)   The rate of change of allele frequencies must be greater than 1 percent from generation to generation.

Question 6

Although selection tends to eliminate deleterious alleles from populations,these mutations often persist because they are frequently created again.The rate at which deleterious alleles are being eliminated by selection is exactly equal to the rate at which new copies are being created by creation is termed ________.[three words]

Accepted Answer

The answer of Although selection tends to eliminate deleterious alleles...

Question 7

List the five assumptions made by the Hardy-Weinberg equilibrium principle that are necessary to illustrate that evolution is NOT occurring from generation to generation,and provide a one- or two- sentence explanation of the importance of each assumption.

Accepted Answer

The answer of List the five assumptions made by the...

Question 8

Chun-Hong Chen and colleagues (2007)designed a new gene that would carry a strong selective advantage and confer the resistance to malaria on free-living mosquitoes.What was the acronym given this gene,and what does the acronym stand for?

Accepted Answer

The answer of Chun-Hong Chen and colleagues (2007)designed a new...

Question 9

In large populations,the Hardy-Weinberg equilibrium principle can be used to determine whether evolution is occurring.For instances where allelic frequencies are indicated by p and q,the resultant genotype frequencies are indicated by which of the following equations?

Accepted Answer

A)   p² + q²
B)   p² + pq + q²
C)   p² + 2pq + q²
D)   p2 + (pq) ² + q²

Question 10

Cystic fibrosis in humans is caused by a recessive loss-of-function mutation in a locus on chromosome 7 that encodes for a protein called ________.[five words]

Accepted Answer

The answer of Cystic fibrosis in humans is caused by...

Question 11

If there were a high allele frequency for the CCR5-32 coreceptor,and the rate of infection with HIV was high as well,one would expect the frequency of the CCR5-32 coreceptor allele to ________.

Accepted Answer

A)   remain the same due to the lethality of AIDS
B)   remain the same due to the population maintaining Hardy-Weinberg equilibrium
C)   fall quickly due to heterozygote selection
D)   rise quickly and confer resistance on a large part of the population

Question 12

A hypothetical population has two alleles for a gene: A and a.In a random sample of 100 individuals,20 are homozygous for a,20 are homozygous for A,and 60 are heterozygous.What is the frequency of A?

Accepted Answer

A)   20%
B)   25%
C)   50%
D)   60%
E)   80%

Question 13

Discuss the experiments Cavener and Clegg (1981)performed in order to demonstrate that natural selection occurred by observing the cumulative change in allele frequencies in populations of Drosophila melanogaster that were subjected to high levels of alcohol.Be sure to discuss the methodology employed,and the significance of the Adhˢ and Adhᶠ alleles in reproductive success.

Accepted Answer

The answer of Discuss the experiments Cavener and Clegg (1981)performed...

Question 14

The null hypothesis,which demonstrates that evolution is not occurring from generation to generation,is known as the ________ model.

Accepted Answer

A)   Bateman
B)   Hardy-Weinberg
C)   Fisher stability
D)   Mendelian stability

Question 15

Explain the composition of the Drosophila melanogaster compound chromosomes used in the experiments of Foster and colleagues (1972),the mechanism by which these chromosomes segregate during meiosis,and the evolutionary implications of the strong underdominance that was observed.

Accepted Answer

The answer of Explain the composition of the Drosophila melanogaster...

Question 16

Chun-Hong Chen and colleagues (2007)designed a new gene that would carry a strong selective advantage and confer the resistance to malaria on free-living mosquitoes.The gene was termed Medea,and this acronym stands for which of the following?

Accepted Answer

A)   Maternal-effect depleted embryonic activation
B)   Maternal-effect dominant embryonic activation
C)   Maternal-effect deleterious embryonic arrest
D)   Maternal-effect dominant embryonic arrest

Question 17

Two processes that can maintain rare or deleterious alleles in populations are ________ [four words] and ________.[two words]

Accepted Answer

The answer of Two processes that can maintain rare or...

Question 18

The statistical test used to determine whether the quantitative allele frequency results of an experiment fall within reasonable limits,or whether the null hypothesis is violated and the measured outcomes are significantly different than those expected is called the ________.[three words]

Accepted Answer

The answer of The statistical test used to determine whether...

Question 19

A group of interbreeding individuals and their offspring is known as a(n)________.

Accepted Answer

The answer of A group of interbreeding individuals and their...

Question 20

An analysis showing the heterozygote superiority of the ΔF508 allele of CFTR demonstrates increased resistance to infections with the bacteria that cause ________.

Accepted Answer

A)   pneumonia
B)   typhoid fever
C)   scarlet fever
D)   bubonic plague
E)   tuberculosis

Exam 6: Mendelian Genetics in Populations I: Selection and Mutation