Deck 13: Chromosomes, mapping, and the Meiosisinheritance Connection

Question 1

Genetic exchange between 2 homologous chromosomes is called

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

Answer 1

C

Question 2

The most common fatal genetic disorder of Caucasians is

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

Answer 2

B

Question 3

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.
E)dominant allele on an autosome.

Answer 3

A

Question 4

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.
E)Down syndrome.

Question 5

Humans who have lost one copy of an autosome are called

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

Question 6

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.
E)for nourishing the fetus.

Question 7

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.
E)chromosome inactivation.

Question 8

The theory of chromosomal inheritance was first proposed by

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

Question 9

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.
E)the type of blood cell it is found in.

Question 10

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.
E)chromosome inactivation.

Question 11

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

Question 12

Allele pairs are most likely to assort independently of one another when

A)they control unrelated traits.
B)they control related traits.
C)they are on the same chromosome.
D)they are sex-linked.
E)they are on different chromosomes.

Question 13

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.
E)2 pairs of alleles.

Question 14

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

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

Question 15

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.
E)codominant.

Question 16

________ 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
E)Hemophilia

Question 17

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 18

In humans,individuals with trisomy of the ________ chromosome are most likely to survive until adulthood.

A)3rd.
B)13th.
C)15th.
D)18th.
E)21st.

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.
E)she is genetically a normal fertile female.

Question 20

The geneticist who discovered the white eye mutation in Drosophila and helped establish that genes are carried on chromosomes was

A)Mendel.
B)Sutton.
C)Sturtevant.
D)Janssens.
E)Morgan.

Question 21

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

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

Question 22

A 39-year-old woman and 42-year-old man are expecting a child; the woman is 6 weeks pregnant.The pregnancy is categorized as high risk due to the age of the parents,and the couple would like to have prenatal testing done to see if any genetic disorders are present in the fetus.Their doctor should suggest

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

Question 23

In humans,if nondisjunction 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 24

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 25

Any genetic differences between individuals in a population are called

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

Question 26

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 27

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 inheritance 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.
E)Determination of the gender of any human or bird offspring is related to the environmental conditions at the time of conception.

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

In Drosophila,the allele red eyes (bw+)is dominant to the allele for brown eyes (bw).At another gene locus on the same chromosome,the allele for thin wing veins (hv+)is dominant to the allele for heavy wing veins (hv).Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F₁ progeny.
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 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

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.
E)Even though Huntington's disease is lethal,it improves chances for reproduction before the person dies.

Question 32

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 33

In Drosophila,the allele red eyes (bw+)is dominant to the allele for brown eyes (bw).At another gene locus on the same chromosome,the allele for thin wing veins (hv+)is dominant to the allele for heavy wing veins (hv).Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F₁ progeny.
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 34

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%.
E)double the level of expression of genes on the Y chromosome.

Question 35

In humans,if nondisjunction 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 36

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 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

Which of the following animals is a genetic male?

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

Question 39

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

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

Question 40

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 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

At an autosomal gene locus in humans,the allele for brown eyes is dominant over the allele for blue eyes.At another gene locus,located on the X chromosome,a recessive allele produces colorblindness while the dominant allele produces normal color vision.A heterozygous brown-eyed woman who is a carrier of colorblindness has a child with a blue-eyed man who is not colorblind.An ultrasound test shows that the child is a girl.What is the probability that she will be colorblind? (Enter the probability as a percent.Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

Question 43

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 44

In humans,hemophilia is caused by a recessive allele on the X chromosome.Suppose a man with hemophilia has children with a healthy woman whose mother had hemophilia.If an ultrasound test shows that their first child is a girl,what is the probability that she has hemophilia? (Enter the probability as a percent.Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

Question 45

At an autosomal gene locus in humans,the allele for brown eyes is dominant over the allele for blue eyes.At another gene locus,located on the X chromosome,a recessive allele produces colorblindness while the dominant allele produces normal color vision.A heterozygous brown-eyed woman who is a carrier of colorblindness has children with a blue-eyed man who is not colorblind.What is the probability that their first child will be a blue-eyed female who has normal color vision? (Enter the probability as a percent.Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

Question 46

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 47

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
E))098 cM

Question 48

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 49

In fruit flies (Drosophila melanogaster)there is a dominant allele for red eyes and a recessive allele for white eyes.These alleles are located on the X chromosome.If a heterozygous red-eyed female is mated with a white-eyed male,what percentage of the offspring are expected to be white-eyed females? (Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

Question 50

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 51

In humans,hemophilia is caused by a recessive allele on the X chromosome.Suppose a man with hemophilia has children with a healthy woman whose mother had hemophilia.What is the probability that their second child will have hemophilia? (Enter the probability as a percent.Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

Question 52

In Drosophila,the allele red eyes (bw+)is dominant to the allele for brown eyes (bw).At another gene locus on the same chromosome,the allele for thin wing veins (hv+)is dominant to the allele for heavy wing veins (hv).Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F₁ progeny.
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 53

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%.
E)level off at 100%.

Question 54

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 55

In the fruit fly Drosophila,there is a dominant gene for normal wings and its recessive allele for vestigial wings.At another gene locus on the same chromosome,there is a dominant gene for red eyes and its recessive allele for purple eyes.A male that was heterozygous at both gene loci was mated with a female that was homozygous for both recessive alleles and the following results were observed among the offspring:
Normal wings and red eyes - 420
Vestigial wings and red eyes - 80
Normal wings and purple eyes - 70
Vestigial wings and purple eyes - 430
According to these data,what is the distance,in centimorgans,between these 2 gene loci? (Enter the number only without the units.For example,100 cM would be entered as 100)

Question 56

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.

Question 57

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 58

In Drosophila,the allele red eyes (bw+)is dominant to the allele for brown eyes (bw).At another gene locus on the same chromosome,the allele for thin wing veins (hv+)is dominant to the allele for heavy wing veins (hv).Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F₁ progeny.
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