Deck 19: Population Genetics and Human Evolution

Question 1

The relatively high percentage of individuals in West Africa who are heterozygous for the sickle cell trait is an example of _____.

A) natural selection
B) genetic drift
C) spontaneous mutational spread
D) heterozygote disadvantage
E) the founder effect

Answer 1

A

Question 2

The availability of genomic data has allowed scientists to construct more accurate phylogenetic trees than those based on fossil evidence alone.

Answer 2

True

Question 3

Hardy and Weinberg showed that the allele frequencies in a non-evolving population change with successive generations.

Answer 3

False

Question 4

Genetic drift is a random process that can change the genetic structure of a population.

Question 5

The rapid change in G6PD allele frequency and the correlation of this allele with areas of high rates of malaria suggests that ____ explains this change in G6PD allele frequency.

A) genetic drift
B) artificial selection
C) X-linked inheritance
D) the founder effect
E) natural selection 

Question 6

The genetic variability of a population is solely dependent on the generation of mutations.

Question 7

The Hardy-Weinberg law can be used to calculate allele and genotype frequencies without genetic testing.

Question 8

According to genetic evidence,the migration of H.sapiens out of Africa replaced other human populations,including Neanderthals and H.erectus,leading to their extinction.

Question 9

Albinism is a recessive trait controlled by a single gene.If the frequency of albinos in a population is 0.25,what is the expected frequency of heterozygotes for this trait?

A) 0.25
B) 0.50
C) 0.75
D) 0.90
E) 1.00

Question 10

Since males have only one X chromosome,the allele frequency of an X-linked trait is equal to the number of males with the recessive phenotype.

Question 11

The Hardy-Weinberg law is used to calculate allele and genotype frequencies ____.

A) in small populations
B) when mating is random
C) in migrating populations
D) when some alleles confer an evolutionary advantage over other alleles
E) the population descends from a single ancestor

Question 12

Assume the trait for brown eyes is completely dominant to blue eyes and this trait is controlled by a single gene.If 400 people in a population of 10,000 have blue eyes,how many people would be expected to be heterozygous for this trait? (Hint: Use the Hardy-Weinberg formula.)

A) 8,000
B) 5,400
C) 3,200
D) 960
E) 320

Question 13

There is significantly more genetic variation between human populations than within them.

Question 14

Most geneticists would agree that human races are distinct genetic entities.

Question 15

All evolutionary ancestors of modern humans have been discovered and identified.

Question 16

In a Hardy-Weinberg equilibrium,as the frequencies of homozygous genotypes increase,the frequency of the heterozygous genotype _____.

A) doubles
B) is reduced by a factor of 10
C) increases linearly
D) decreases linearly
E) remains the same

Question 17

A population that is in genetic equilibrium is said to ____.

A) have an equal number of homozygotes as heterozygotes for a given trait
B) deviate from the Hardy-Weinberg law
C) require genetic testing for estimation of allele frequencies
D) lose genetic variation with each generation
E) have an allele or alleles that remain constant generation to generation

Question 18

A loss of 90% of the population in the Pingelap atoll from a typhoon in 1775 resulted in a high percentage of the current population being affected by achromatopsia.As a result,all of these affected individuals _____.

A) have normal vision
B) are descendants of one of the 20 original survivors
C) receive genetic testing and genetic counseling
D) have exceptional hearing
E) are descendants of the 20 original survivors

Question 19

A predictable effect of genetic drift in a small population is an increase in _____.

A) mutations
B) dominant alleles
C) recessive alleles
D) genetic variation
E) homozygosity

Question 20

According to the theory of evolution,those best adapted to the environment will _____.

A) survive and reproduce
B) not survive
C) produce offspring that are genetically identical to the parents
D) have lower fertility rates
E) have fewer offspring on average

Question 21

If 0.04% (0.0004)of the people in a population has sickle cell anemia,the percent of heterozygotes in the population must be _____________________ percent.

Question 22

According to the _____,modern humans originated in,and migrated out of,East Africa.

A) haplotype data of mitochondrial DNA sequences
B) haplotype data of Y chromosome sequences
C) out-of-Africa model
D) multiregional model
E) fossil record

Question 23

Hemophilia is an X-linked trait caused by the allele h. About 1 in 10,000 males (0.0001)has hemophilia. The frequency of the h allele in males is therefore _____________________.

Question 24

The frequency of a certain genotype in a population is called _____________________.

Question 25

Of the following hominin species,from which did H.sapiens derive?

A) H. habilis
B) H. rudolfensis
C) H. heidelbergensis
D) H. ergaster
E) H. erectus

Question 26

The gradient distributions of alleles across continents reflect _____.

A) the delineation of new races
B) genetic drift
C) human migration patterns
D) protective alleles
E) natural selection

Question 27

In the Hardy-Weinberg equation,_____________________ represents the dominant allele,while _____________________ represents the recessive allele.

Question 28

The genotypic definition of race states that races are populations of the same species in which allele frequencies differ by ____.

A) 15%-20%
B) 85%
C) 1 in 1000 nucleotides
D) 25%-30%
E) 5%-10%

Question 29

In a large population on a Pacific island,a few individuals had a mutation that caused them to have different colored eyes.After a hurricane,the population was reduced to only a few individuals,but some of those individuals had the rare eye color mutation.Now,after many generations,almost half of the population on this island has different colored eyes.This is an example of _____________________.

Question 30

When applying the Hardy-Weinberg law to a gene with dominant and recessive alleles,calculation of the allele frequencies always begins by writing the frequency of the _____________________ phenotype,then taking the _____________________ of this to obtain the frequency of the recessive allele.

Question 31

Genomic studies of Neanderthals,modern humans,and chimpanzees have confirmed that ____.

A) humans evolved from Denisovans
B) humans and Neanderthals interbred
C) humans and Neanderthals are 98.8% genetically identical
D) humans are direct descendants of Neanderthals
E) there is a 5% difference in the coding regions of the human genome vs. the chimpanzee genome

Question 32

The phenotypic differences between chimps and humans is best explained by _____.

A) the high variation in the number of different genes between the two species
B) the high number of inversion sequences
C) epistatic changes to genes
D) patterns of gene expression and regulation
E) the large amount of "junk DNA" found in chimpanzee genomes

Question 33

The observation that SNPs account for most of the differences in the coding regions between the human and chimpanzee genomes suggests that ____.

A) the two genomes are too different to suggest an evolutionary relationship
B) Neanderthals descended directly from chimpanzees
C) small changes in amino acid sequences account for big differences in phenotype
D) most of the differences in phenotype are due to DNA sequence changes
E) humans descended directly from chimpanzees

Question 34

Because of the _____________________,traits carried by early settlers are found in a large fraction of the descendent population.

Question 35

The _____________________ law measures allele and genotype frequencies in a population without the need for genetic testing.

Question 36

The ultimate source of new alleles and genetic variability is _____________________.

Question 37

Which population has a small percentage of Denisovan genes,thus suggesting interbreeding?

A) Asians
B) Melanesians
C) H. floresiensis
D) Neanderthals
E) chimpanzees

Question 38

The taxonomic category that includes species of apes,humans,and their ancestors is known as ____.

A) hominids
B) hominins
C) hominoids
D) australopithecines
E) apes

Question 39

Humans differ from each other by 1 in 1000 to 1 in 5000 nucleotides,while chimpanzees differ from each other by 1 in 500 nucleotides.This suggests that _____.

A) humans are a younger species
B) humans are an older species
C) humans descended directly from chimpanzees
D) chimpanzees descended directly from humans
E) chimpanzees and humans have identical proteomes

Question 40

In a hypothetical population of 1,000 people,there is a hypothetical trait called pink toe.People who are homozygous dominant have red toes,those who are homozygous recessive have white toes,and those who are heterozygous have pink toes.If 400 people have red toes,the number of people with pink toes is _____________________.

Question 41

Diagram the evolutionary relationships between Neanderthals and chimpanzees based on genomic data.

Question 42

Heterozygotes for the Tay-Sachs disease allele appear to have greater than normal resistance to _____________________,which supports the theory that _____________________ explains why this harmful allele persists in the gene pool.

Question 43

On average,humans differ by _____________________% of their genomic sequences.

Question 44

Outline the assumptions made in establishing the Hardy-Weinberg law.

Question 45

A(n)_____________________ depicts the evolutionary relationships between related species.

Question 46

Why is it that mutation,acting alone,has little effect on allele frequency,and therefore evolution? What other factors will magnify the effect?

Question 47

The observation that some modern humans contain Neanderthal DNA suggests _____________________ occurred between H.sapiens and Neanderthals.

Question 48

What is the effect of genetic drift on evolution? How does the founder effect work to cause change in allele frequency?

Question 49

Genetic evidence has revealed that H.sapiens diverged from _____________________ 100,000 years ago,while Neanderthals diverged from this species 300,000 years ago,suggesting that modern humans did not descend directly from Neanderthals.

Question 50

Do you agree with geneticists that there is no genetic basis to divide humans into races?  Why or why not?

Question 51

One would think that deleterious genes would be eliminated by natural selection,yet we have two human genetic disorders with a high carrier frequency,sickle-cell anemia and cystic fibrosis.Why has this high frequency for these conditions remained in the population?

Question 52

The idea that H.erectus populations in Africa,the Middle East,and Asia all collectively interbred and evolved into H.sapiens is called the _____________________ model.

Question 53

According to the Hardy-Weinberg law,the genotype frequencies of dominant homozygotes,heterozygotes,and recessive homozygotes are represented by p2,q2,and 2pq,respectively,where p is the frequency of the dominant allele and q is the frequency of the recessive allele. Explain how this formula was derived.

Question 54

The taxonomic category that includes all bipedal primates is called _____________________.

Question 55

Comparative genome studies show that humans and _____________________ shared a common ancestor approximately 5.4 to 6.3 million years ago.

Question 56

The measure of differential survival and reproductive success is termed _____________________.

Question 57

In the U.S.,many states passed laws against miscegenation,or marriage between individuals of different races.What genetically based arguments would you use in support or opposition to such laws?

Question 58

Genomic studies using _____________________ can identify an individual's ancestral continent.

Question 59

During the eugenics movement of the 1900s,it was believed that individuals affected with certain genetic disorders should be sterilized to prevent transmitting the gene to future generations.Would such measures be effective?  Why or why not?

Question 60

Compare and contrast the out-of-Africa model and multiregional theories of the origin of modern man.Which theory is supported by the preponderance of genetic evidence? What type of evidence supports the other theory