Deck 15: Changing Allele Frequencies

Question 1

The collection of deleterious alleles in a population is called the

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

Answer 1

C

Question 2

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.
E) anti-semitism.

Answer 2

A

Question 3

A social characteristic that can create clines is

A) religion.
B) marriage customs.
C) language.
D) geographic barriers.
E) whether gay marriage is legal.

Answer 3

C

Question 4

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) gene therapy.
E) consanguinity.

Question 5

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.
E) new mutation.

Question 6

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.
E) migration.

Question 7

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.
E) Hardy-Weinberg equilibrium.

Question 8

_______ maintains deleterious alleles in a population.

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

Question 9

A small group of islanders leave "island A" and travel to "island B." After several generations on island B,a researcher finds that a large percentage of the population is left-handed.Left-handedness is a relatively rare trait on island A.A genetic event that explains this is

A)a population bottleneck.
B)genetic load.
C)a founder effect.
D)natural selection.
E)Hardy-Weinberg equilibrium.

Question 10

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) exposure to a devastating infectious disease.
E) nonrandom mating.

Question 11

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.
E) consanguinity.

Question 12

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.
E) too young to be married.

Question 13

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

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

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.
E) have mutated because of radiation exposure.

Question 15

A founder effect within a founder effect occurred among the

A) Old Order Amish of Pennsylvania.
B) Ashkenazi Jewish people of Eastern Europe.
C) Pingelapese people of Micronesia.
D) French Canadians of Quebec.
E) Roma gypsies of Bulgaria.

Question 16

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.
E) in populations that have been through bottlenecks.

Question 17

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) uncles have children with nieces as part of the culture.
E) being a heterozygote for a particular gene protects against an infectious disease.

Question 18

A founder effect occurs when

A) whole populations migrate after a natural disaster.
B) geographic barriers separate populations.
C) small groups of individuals leave a population to start their own.
D) individuals in a population have few children.
E) mutation introduces a new allele into a population.

Question 19

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 own dogs.
E) many people have dominant genetic disorders.

Question 20

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.
E) genetic screening programs identify carriers.

Question 21

Resistance of sickle cell disease carriers to malaria illustrates

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

Question 22

Deleterious alleles are eliminated from populations by

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

Question 23

Many alleles cause 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.
E) Present in 100% of the individuals.

Question 24

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.
E) genetic load.

Question 25

Which of these affects allele frequencies the least?

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

Question 26

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
E)Creutzfeldt-Jakob disease is found among families in Chile,Italy,Tunisia and Libya who were expelled from Spain during the Middle Ages.
F)A chick in a family of turkeys is born who has very unusual light brown plumage - no other relative has this phenotype.

Question 27

Control of human reproduction to achieve a societal goal is called

A) biogenics.
B) eugenics.
C) biodiversity.
D) genetic engineering.
E) natural selection.

Question 28

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.
E) a gene that encodes a protein that includes mostly positively charged amino acids.

Question 29

Darwin thought that all natural selection was 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.
E) removes gene variants that are harmful.

Question 30

_______ 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
E) Genetic drift

Question 31

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

A) malaria.
B) diphtheria.
C) tuberculosis.
D) cholera.
E) sickle cell disease.

Question 32

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.
E) alleles are in Hardy-Weinberg equilibrium.

Question 33

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.
E) due to economic conditions.

Question 34

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.
E) does not occur at the chromosomal level.

Question 35

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.
E) creating bacterial strains that can resist multiple antibiotic drugs.

Question 36

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.
E) genetic testing is better now.

Question 37

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

A) the United States
B) England
C) China
D) Russia
E) All of these

Question 38

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.
E) agricultural selection.

Question 39

_______ 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) Nonrandom mating
E) Genetic drift

Question 40

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

A) malaria.
B) tuberculosis.
C) diarrheal illness.
D) pneumonia.
E) prion diseases.