Deck 13: Chromosomes, Mapping, and the Meiosis-Inheritance Connection

Question 1

Of the 23 pairs of human chromosomes, 22 pairs are homologous and are found in both males and females.These are called ________.

A)bivalents
B)autosomes
C)recombinant chromosomes
D)somatic chromosomes

Answer 1

B

Question 2

Hemophilia is caused by a

A)recessive allele on the X chromosome.
B)dominant allele on the X chromosome.
C)codominant allele on the X chromosome.
D)recessive allele on an autosome.

Answer 2

A

Question 3

A genetic _____ indicates the distances between gene loci measured in terms of the frequency of recombination.

A)map
B)profile
C)pedigree
D)clone

Answer 3

A

Question 4

In Morgan's experiments, the white eye allele in Drosophila was shown to be

A)located on the X chromosome.
B)located on the Y chromosome.
C)dominant.
D)located on an autosome.

Question 5

Huntington's disease is caused by a single dominant allele.It is a lethal disease, yet it persists in the human population.Which of the following statements best describes why?

A)Huntington's disease is sex-linked and every human has at least one X chromosome; thus, the chances are extremely high for this allele to be maintained in the human population.
B)Huntington's disease can present symptoms so mild that they appear to lack dominant expression of the allele in some individuals; in those cases, the allele is passed on to the offspring.
C)While lethal to a parent, Huntington's disease will not be lethal to the offspring since it can skip a generation.
D)Huntington's disease presents symptoms in mid-life, after most people have already had offspring.

Question 6

Occasionally, chromosomes fail to separate during meiosis, leading to daughter cells that have an abnormal number of chromosomes.This phenomenon is called

A)epistasis.
B)nondisjunction.
C)crossing over.
D)pleiotropy.

Question 7

Humans who have lost one copy of an autosome are called

A)haploid.
B)trisomic.
C)bisomic.
D)monosomic.

Question 8

Traits that are controlled by genes located on the X chromosome are said to be ________________.

A)autosomal
B)gametal
C)sex-linked
D)pleiotropic

Question 9

Sickle cell anemia is caused by a defect in the

A)oxygen-carrying pigment hemoglobin.
B)ability of the blood to clot.
C)ability of red blood cells to fight infection.
D)chloride ion transport protein.

Question 10

The theory of chromosomal inheritance was first proposed by

A)Mendel.
B)Morgan.
C)Knight.
D)Sutton.

Question 11

_______________ is a human hereditary disease that is caused by a dominant allele but does not show up in affected individuals until they are in middle age.

A)Cystic fibrosis
B)Sickle cell anemia
C)Tay-Sachs disease
D)Huntington's disease

Question 12

A human female with only one X chromosome is said to have a condition called

A)X chromosome inactivation.
B)Angelman syndrome.
C)Turner syndrome.
D)Klinefelter syndrome.

Question 13

In sickle cell anemia, the defective hemoglobin differs from the normal hemoglobin by

A)the color of the pigment.
B)the size of the molecule.
C)a single amino acid substitution.
D)the total number of amino acids.

Question 14

In humans, the male has an X and a Y sex chromosome.The human female has two X chromosomes.In birds, the female has a Z and a W sex chromosome while the male has two Z chromosomes.Which of the following statements is accurate about which parent determines the gender of the offspring based on inheritace of the necessary sex chromosome?

A)In humans and birds, the male determines the gender of all the offspring.
B)In humans and birds, the female determines the gender of all the offspring.
C)In humans, the male determines the gender of the offspring, and in birds the female determines the gender.
D)In humans, the female determines the gender of the offspring, and in birds the male determines the gender.

Question 15

Genetic exchange between 2 homologous chromosomes is called

A)synapsis.
B)pleiotropy.
C)crossing over.
D)allelic exchange.

Question 16

The number of allele pairs that assort independently in an organism is generally much higher than the number of chromosome pairs.This phenomenon is due to

A)independent assortment.
B)segregation.
C)crossing over.
D)sex-linkage.

Question 17

Amniocentesis is a procedure that is normally used

A)to reduce the risk of genetic disease.
B)for gene therapy.
C)to change the sex of the fetus.
D)for diagnosis of genetic disorders.

Question 18

In Drosophila, the sex of an individual is determined by

A)1 pair of alleles.
B)the number of X chromosomes.
C)the number of Y chromosomes.
D)1 pair of autosomes.

Question 19

If a human female has 2 Barr bodies per cell, it is almost certain that

A)her father had 1 Barr body per cell.
B)her mother also had 2 Barr bodies per cell.
C)she developed from a fertilized egg with 3 X chromosomes.
D)she is genetically a male with female characteristics.

Question 20

The most common fatal genetic disorder of Caucasians is

A)cholera.
B)cystic fibrosis.
C)hemophilia.
D)sickle cell anemia.

Question 21

Any genetic differences between individuals in a population are called

A)markers.
B)alleles.
C)polymorphisms.
D)SNPs.

Question 22

In Drosophila, dosage compensation is controlled by the male-specific lethal (MSL) complex consisting of MSL proteins and roX RNAs.Based on what you know about dosage compensation, the role of the MSL complex in males would be to

A)double the level of expression of genes on the X chromosome.
B)increase the level of expression of genes on the X chromosome by 50%.
C)decrease the level of expression of genes on the X chromosome by 50%.
D)decrease the level of expression of genes on the X chromosome by 100%.

Question 23

In humans, if non-disjunction led to an individual with a genotype of XXY, that person would

A)be female because each cell has two X chromosomes.
B)be male because each cell has one Y chromosome.
C)display both male and female characteristics.
D)not survive.

Question 24

In humans, if an XY individual had a deletion of the SYR gene, that person would

A)develop as a female.
B)have both male and female characteristics.
C)have ambiguous genitalia.
D)develop as a male.

Question 25

In a two-point cross to map genes A and B, you obtained 98 recombinant types and 902 parental types among the offspring.How far apart are these genes?

A)9.8 cM
B)0.98 cM
C)90.2 cM
D)9.02 cM

Question 26

Given that these two gene loci are very closely linked, the phenotypic ratio in the F₂ generation should be closest to

A)1 brown eye, heavy wing veins: 2 red eye, thin wing veins: 1 brown eye, thin wing veins
B)1 brown eye, thin wing veins: 2 red eye, thin wing veins: 1 red eye, heavy wing veins
C)3 red eye, thin wing veins: 1 brown eye, heavy wing veins
D)1 brown eye: 1 red eye: 1 heavy wing veins: 1 thin wing veins

Question 27

A 39-year-old woman is in her sixth week of pregnancy.Due to her advanced age, she is at higher risk for having a baby with Down's syndrome than younger pregnant women.She would like to find out as early as possible whether or not her baby has Down's syndrome.Her doctor should suggest

A)amniocentesis.
B)genetic counseling.
C)chorionic villi sampling.
D)a pedigree analysis.

Question 28

Which offspring inherit all their mitochondrial DNA from their mother and none from their father?

A)daughters
B)sons
C)both sons and daughters
D)neither sons nor daughters

Question 29

Which of the following animals is a genetic male?

A)bird ZW
B)grasshopper XO
C)honeybee diploid
D)Drosophila XXY

Question 30

If you needed to determine the order of genes on a chromosome, you should perform

A)a test cross.
B)a two-point cross.
C)a three-point cross.
D)a SNP test.

Question 31

The classic experiments performed by Creighton and McClintock in Maize

A)provided the initial evidence for genetic recombination.
B)provided evidence that genes located on the same chromosome do not assort independently.
C)allowed for the establishment of the first genetic map.
D)provided evidence for the physical exchange of genetic material between homologues.

Question 32

How many Barr bodies does a normal human female contain in each diploid cell?

A)0
B)1
C)2
D)3

Question 33

In humans, if non-disjunction led to an individual with a genotype of XO, that person would

A)be female because each cell lacks a Y chromosome.
B)be male because each cell has only one X chromosome.
C)display both male and female characteristics.
D)not survive.

Question 34

Nondisjunction of a single pair of autosomes can lead to all of the following except

A)aneuploidy.
B)monosomy.
C)trisomy.
D)euploidy.

Question 35

A test cross can be used to do all of the following except

A)determine whether an individual that displays a dominant phenotype is homozygous for the trait.
B)determine whether an individual that displays a dominant phenotype is heterozygous for the trait.
C)gather genotype information from phenotype information.
D)identify the chromosome on which a gene is located.

Question 36

Which statement about calico cats is false?

A)Calico cats can be male or female.
B)The different colored fur is due to the inactivation of one X chromosome.
C)The variation in coat color is an example of an epistatic interaction.
D)Calico cats are genetic mosaics.

Question 37

If an XY human had a genetic disorder that causes insensitivity to androgens, that person's genotype and phenotype would be

A)XX, female.
B)XX, male.
C)XY, female.
D)XY, male.

Question 38

What would be the results of a test cross with the F₁ flies?

A)1 brown eye, thin wing veins: 1 red eye, heavy wing veins
B)1 brown eye, heavy wing veins: 1 red eye, thin wing veins
C)1 brown eye, thin wing veins: 2 red eye, thin wing veins: 1 red eye, heavy wing veins
D)1 brown eye, heavy wing veins: 2 red eye, thin wing veins: 1 red eye, thin wing veins

Question 39

Given that these two gene loci are very closely linked, the genotypic ratio in the F₂ generation should be closest to

A)1:2:1
B)1:1:1:1
C)9:3:3:1
D)3:1

Question 40

What is the relationship between recombination frequency and the actual physical distance on a chromosome?

A)As physical distance increases, the recombination frequency increases in a linear fashion.
B)As physical distance increases, the recombination frequency decreases in a linear fashion.
C)As physical distance increases, the recombination frequency first increases in a linear fashion, but gradually levels off to a frequency of 0.5.
D)As physical distance increases, the recombination frequency first increases, but then decreases.

Question 41

Suppose you are carrying out a series of crosses with an insect where the mechanism of sex determination is unknown.You discover a mutant female with short bristles and decide to cross it with a wild type male that has normal bristles.Half of the F₁ progeny have short bristles but all of these short-bristled F₁ progeny are males.Based on these results, a valid hypothesis would be

A)Males are ZW, females are ZZ, and short bristles are caused by a dominant allele on the Z chromosome.
B)Males are ZZ, females are ZW, and short bristles are caused by a recessive allele on the Z chromosome.
C)Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the W chromosome.
D)Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the Z chromosome.

Question 42

Genetic maps are based on recombination frequencies.Because both odd and even numbers of crossovers can occur between any two gene loci, as the physical distance between two loci increases, the maximum recombination frequency levels off at 50%.However, suppose you discovered a species where only an even number of crossovers can occur between any two gene loci.In this case, as the physical distance between two loci increases, you would expect the maximum recombination frequency to

A)remain at zero.
B)increase with no limit.
C)level off at 25%.
D)level off at 75%.

Question 43

In 1910, Morgan did a series of experiments with the fruit fly Drosophila, an organism where females are XX and males are XY.When a mutant male fly with white eyes was crossed with a wild type female with red eyes, none of the F₁ progeny had white eyes but 18% of the F₂ progeny had white eyes.Unexpectedly, all of these white-eyed F₂ flies were males.Based on these results, Morgan concluded that white eyes is caused by a recessive X-linked allele.Suppose Morgan had found that half of the F1 progeny had white eyes but all of these white-eyed F₁ flies were females.In this case, a valid hypothesis would be

A)White eyes is caused by a recessive Y-linked allele.
B)White eyes is caused by a dominant Y-linked allele.
C)White eyes is caused by a dominant X-linked allele.
D)White eyes is caused by a dominant autosomal allele.

Question 44

Morgan's student Sturtevant demonstrated that the recombination frequencies between a series of linked genes is additive.Examine the following recombination data from Sturtevant, and determine the proper order of the genes on the Drosophila X chromosome.Assume y is in the 0.0 position.Gene 1 Gene 2 Recombination frequency yellow(y) vermilion(y) 0.322 vermilion miniature(m) 0.030 white(w) vermiliom 0.297 yellow white 0.010 white miniature 0.337

A)y m v w
B)y w v m
C)y m w v
D)y w m v

Question 45

How did the development of anonymous markers aid in the production of a human genetic map?

A)Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques.The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA.Such information was essential to the generation of a human genetic map.
B)Anonymous markers are genetic markers that cause a detectable phenotype and can't be detected by molecular techniques.The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA.Such information was essential to the generation of a human genetic map.
C)Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques.The markers correspond to specific and unique genetic regions, thereby allowing for the identification and ordering of particular segments of the chromosome.Such information was essential to the generation of a human genetic map.

Question 46

Why isn't mitochondrial DNA a unique identifier?

A)Mitochondrial DNA is inherited through the paternal lineage.All offspring inherit their father's mitochondria, and therefore the same mitochondrial DNA.As a result, all family members that share a paternal lineage would have the same mitochondrial DNA.Mitochondrial DNA can therefore be used to confirm or eliminate a person's relationship within a paternal line, but cannot be used to identify a specific individual.
B)Mitochondrial DNA is inherited through the maternal lineage.All offspring inherit their mother's mitochondria, and therefore the same mitochondrial DNA.As a result, all family members that share a maternal lineage would have the same mitochondrial DNA.Mitochondrial DNA can therefore be used to confirm or eliminate a person's relationship within a maternal line, but cannot be used to identify a specific individual.
C)Mitochondrial DNA is inherited through the maternal lineage.All female offspring inherit their mother's mitochondria, and therefore the same mitochondrial DNA.As a result, all female family members that share a maternal lineage would have the same mitochondrial DNA.Mitochondrial DNA can therefore be used to confirm or eliminate a person's relationship within a maternal line, but cannot be used to identify a specific individual.

Question 47

Which of the following will help you distinguish between the two final suspects?

A)single nucleotide polymorphisms (SNPs)
B)human genome map
C)linkage data
D)markers on the Y chromosome

Question 48

Why can't you use mitochondrial DNA to distinguish between these two suspects?

A)The sequence of mitochondrial DNA has not yet been determined.
B)The brothers share the same mitochondrial DNA.
C)There are no molecular techniques available that allow one to analyze mitochondrial DNA.
D)Because mitochondrial DNA is inherited in a paternal pattern.

Question 49

In some human populations, the proportion of individuals who are heterozygous for the sickle cell allele is much higher than would be expected by chance alone.Why?

A)Individuals with two normal alleles have an advantage over heterozygous individuals.
B)Individuals with two harmful alleles have an advantage over heterozygous individuals.
C)Individuals with two harmful alleles have an advantage over individuals with two normal alleles.
D)Heterozygous individuals have an advantage over individuals with two normal alleles.

Question 50

A deletion of a particular stretch of chromosome 15 can cause either Prader-Willi syndrome or Angelman syndrome, depending on

A)the parental origin of the normal and deleted chromosome.
B)whether or not the region is methylated properly.
C)whether a translocation event has occurred.
D)whether a nondisjunction event has occurred.