Deck 15: Changing Allele Frequencies

Question 1

In human populations,Hardy-Weinberg equilibrium is seen

A)in small,isolated communities.
B)in populations with many immigrants.
C)in communities founded by a small number of people.
D)infrequently and in large communities with random mating.

Answer 1

D

Question 2

Many alleles cause phenylketonuria (PKU).A unique mutation found only in Yemenite Jews is probably

A)more ancient than other PKU mutations.
B)a result of genetic drift.
C)due to a strong heterozygote advantage.
D)identical to the original allele.

Answer 2

B

Question 3

The collection of deleterious alleles in a population is called the

A)mutation load.
B)mutation bottleneck.
C)genetic load.
D)genome polymorphism.

Answer 3

C

Question 4

In an endogamous community,

A)many people marry people from within the community.
B)many people marry people from another country.
C)many people marry blood relatives.
D)many people have dominant genetic disorders.

Question 5

The prevalence of a Y chromosome with the same sequences as Genghis Khan illustrates

A)mutation.
B)natural selection.
C)nonrandom mating.
D)gene therapy.

Question 6

_____ maintains deleterious alleles in a population.

A)Mutation
B)Migration
C)Random mating
D)Natural selection

Question 7

A sharp cline may indicate

A)a sudden increase in the mutation rate.
B)a population bottleneck.
C)a geographical obstacle,such as a mountain.
D)nonrandom mating.

Question 8

In human populations,inbreeding results in

A)fewer heterozygotes and more homozygotes.
B)more heterozygotes and fewer homozygotes.
C)about equal numbers of homozygotes and heterozygotes.
D)only heterozygotes.

Question 9

Clines are created when

A)emigrants remove alleles and immigrants introduce alleles.
B)immigrants remove alleles and emigrants introduce alleles.
C)different genes mutate in different geographical regions.
D)men marry their nieces as part of their culture.

Question 10

A founder effect occurs when

A)geographic barriers separate populations.
B)some individuals leave a larger group.
C)individuals in a population have few children.
D)mutations introduce new alleles into a population.

Question 11

Consanguineous marriages are between men and women who are

A)from different cultures.
B)"blood" relatives.
C)carriers of a disorder.
D)from the same town.

Question 12

In the science fiction film,When Worlds Collide,100 individuals are selected to leave a doomed Earth in a spaceship to re-establish humanity elsewhere.This scenario illustrates

A)a founder effect.
B)a mutation effect.
C)a population funnel.
D)a deleterious allele.

Question 13

Genetic disorders such as Tay-Sachs disease,Bloom syndrome,Gaucher disease,and Canavan disease are more common in Ashkenazi Jewish populations because

A)spontaneous mutations occur more frequently in this group.
B)the gene pool has been highly variable over thousands of years.
C)microevolution has not influenced this culture.
D)their history includes several population bottlenecks.

Question 14

To determine the evolutionary history of a gene,geneticists assume that the most prevalent alleles in a population

A)are dominant.
B)have mutated the most.
C)are the oldest.
D)are the most recently acquireD.

Question 15

A social characteristic that can create clines is

A)political preferences.
B)marriage customs.
C)language.
D)geographic barriers.

Question 16

Members of two populations in different parts of the world have the same form of inherited breast cancer.The affected individuals in each population have only one specific mutation,but it is different between the two populations.An explanation for this mutation difference among these populations is

A)a founder effect.
B)mutations associated with religion.
C)random mating.
D)Hardy-Weinberg disequilibrium.

Question 17

When all individuals in a population with a certain illness have the same mutation,which present-day patients inherited from shared ancestors,it is an evidence of

A)random mating.
B)migration.
C)population bottlenecks
D)founder effect.

Question 18

A typhoon devastates a population on "island A" and only a few individuals survive.Several generations later,the replenished population suffers from several inherited disorders that are very rare in other groups.A genetic event that explains this is

A)a population bottleneck.
B)genetic load.
C)a founder effect.
D)natural selection.

Question 19

The gradual change in specific human mitochondrial DNA sequences along a river illustrates

A)a founder effect.
B)a population bottleneck.
C)a cline.
D)spontaneous mutation.

Question 20

The fact that nearly everyone on the island of Sardinia has the same X chromosome sequence indicates that the population has experienced

A)mutation.
B)natural selection.
C)nonrandom mating.
D)consanguinity.

Question 21

A person who is a heterozygote for G6PD deficiency is protected against

A)malariA.
B)diphtheria.
C)tuberculosis.
D)sickle cell disease.

Question 22

Resistance of sickle cell disease carriers to malaria illustrates

A)genetic drift.
B)a population bottleneck.
C)balanced polymorphism.
D)a founder effect.

Question 23

In Darwin's time,natural selection was thought to be primarily negative.However,we have since learned that positive selection is a powerful force,and it

A)creates new gene variants that enhance the phenotype.
B)retains gene variants or combinations that promote successful reproduction.
C)enables people to resist infectious diseases.
D)enables us to alter our genotypes.

Question 24

Darwin bred pigeons to have particular traits.Today people breed dogs,cats,horses,and other animals for the same reason.These activities illustrate

A)negative selection.
B)positive selection.
C)artificial selection.
D)veterinary selection.

Question 25

Balanced polymorphism explains why carriers of cystic fibrosis are relatively resistant to

A)malariA.
B)tuberculosis.
C)diarrheal illness.
D)pneumonia.

Question 26

Deleterious alleles are eliminated from populations by

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

Question 27

_____ in the human population reduced the incidence and virulence of tuberculosis in the early twentieth century.

A)Natural selection
B)Mutation
C)Migration
D)Nonrandom mating

Question 28

The population of HIV variants in a person's body changes during the course of infection due to

A)natural selection.
B)mutation.
C)migration.
D)genetic drift.

Question 29

Natural selection can alter gene frequencies in a population because

A)carriers of inherited disease rarely survive to reproduce.
B)it maintains alleles that improve survival to sexual maturity.
C)it compensates for defects caused by deleterious alleles.
D)individuals with deleterious alleles selectively interbreeD.

Question 30

Natural selection has fueled the rise in MRSA (methicillin-resistant Staphylococcus aureus)infection by

A)enabling people to use a greater variety of antibiotic drugs to fight the infection.
B)inactivating a greater variety of antibiotic drugs.
C)enabling certain bacterial variants to survive in the presence of many antibiotic drugs.
D)killing all bacteria exposed to antibiotics,including helpful ones.

Question 31

Which of these affects allele frequencies the least?

A)natural selection
B)mutation
C)migration
D)genetic drift

Question 32

Which of these best represents natural selection?

A)Recessive albinism is more common among the Hopi of Arizona than in the general population of the U.S.
B)A gradual change in specific human mitochondrial DNA sequences occurs along the Nile river in Egypt.
C)ABO blood type frequencies are similar in northern Africa,southern Spain,and the middle east.
D)Lactose tolerant alleles are very prevalent in herding populations that drink milk as a staple.

Question 33

In _____,people with a serious genetic disorder are not permitted to have children.

A)the United States
B)England
C)China
D)Russia

Question 34

The frequency of the allele that causes sickle cell disease is higher in some populations than in others because

A)the gene mutates at different frequencies in different parts of the world.
B)the incidence of malaria differs in different parts of the world.
C)sickle cell disease screening is better in developed countries.
D)heterozygotes are resistant to cholera.

Question 35

Mutation differs from other sources of genetic variation because it

A)always harms the phenotype.
B)is unpredictable.
C)only affects some populations.
D)introduces a change,rather than mixing up existing DNA sequences.

Question 36

Control of human reproduction to achieve a societal goal is called

A)biogenics.
B)eugenics.
C)biodiversity.
D)natural selection.

Question 37

_____ in the mycobacterium tuberculosis population reduced the incidence and virulence of tuberculosis in the early twentieth century.

A)Natural selection
B)Mutation
C)Migration
D)Genetic drift

Question 38

In 1910,Charles Davenport opened the Eugenics Record Office at Cold Spring Harbor.He believed "feeblemindedness" was

A)not inherited.
B)autosomal dominant.
C)X-linked.
D)autosomal recessive.

Question 39

A genetic signature for positive selection is

A)a gene sequence present in humans and other primates,but with at least one amino acid difference in the encoded protein in humans.
B)a gene that is unique to humans.
C)a gene sequence present in humans and other primates,but with no amino acid sequence differences.
D)a gene that encodes a protein that makes the individual more sexually attractive.