Genetics From Genes to Genomes Leland Hartwell 4th Edition Test Bank

Genetics From Genes to Genomes Leland Hartwell 4th Edition Test Bank

Description

Chapter 18 Using Genetics to Study Development

Fill in the Blank Questions

1. Cells ________________ from each other during embryonic development to form hundreds of different cell types.

________________________________________

2. When a loss-of-function mutation results in a completely nonfunctional protein it is termed _________ mutation.

________________________________________

3. When a loss-of-function mutation results in a partially nonfunctional protein it is termed _________ mutation.

________________________________________

4. When a loss-of-function mutation results in a nonfunctional protein under certain conditions (such as temperature) it is termed _________ mutation.

________________________________________

5. When a loss-of-function mutation has a dominant effect it is termed________ _______ mutation.

________________________________________

6. An experimental strategy that uses dsRNA to deplete protein products in a cell is called ___________.

________________________________________

7. __________________ gene expression is when a gene is expressed at an abnormal time or place.

________________________________________

8. A ______________________ is a common motif in proteins with developmental significance.

________________________________________

9. ________________ are genetic mosaics in which the cells of different genotypes come from two different individuals.

________________________________________

10. A protein tagged with GFP is an example of a(n) _____________ protein.

________________________________________

11. Development requires progressive changes in _____________________.

________________________________________

12. The anterior region of a Drosophila embryo is determined by the deposition of maternal ______________ transcripts.

________________________________________

13. Embryos produced from mothers lacking a functional bicoid (bcd) gene do not develop ________________.

________________________________________

14. Maternal hunchback (hb) mRNA transcripts are distributed _____________ in the egg prior to fertilization.

________________________________________

15. ____________________ are molecules whose concentration determines the developmental fate of a cell.

________________________________________

Multiple Choice Questions

16. Which of the following is not one of the three characteristics of value to geneticists for model organisms?

A. ease of cultivation

B. rapid reproduction

C. small size

D. small genome

17. Which of the following is not a taboo on the use of humans in genetics studies?

A. phenotypic analysis

B. experimental manipulation of affected individuals

C. forced matings

D. deliberate production of mutants

18. Evolution has had what effect on development in various organisms?

A. varying

B. conservation of many genes and genetic pathways

C. removal of all mutations.

D. none

19. Mutations that disrupt the earliest stages of human development almost always cause

A. no effect.

B. polydactyly.

C. spontaneous abortion.

D. disruption of the segmented body plan.

20. Development occurs properly due to gene expression

A. at the right time.

B. in the right place.

C. in the right amount.

D. All of the choices are correct.

21. If you wanted to study cellular lineage, which model organism would be best suited?

A. E. coli

B. S. cerevisiae

C. C. elegans

D. M. musculus

22. Which of the following model organisms would be easiest to study recessive mutations using complementation analysis?

A. S. cerevisiae

B. C. elegans

C. M. musculus

23. The Aniridia gene in humans is involved in eye formation. Although eye development is very different in flies, this gene is highly conserved. What is its homolog in Drosophila?

A. eyeless (ey)

B. Pax-6

C. noeye

D. ommatidia

24. A loss-of-function mutation that depends on special circumstances is called

A. null.

B. hypomorphic.

C. conditional.

D. dominant-negative.

25. Which of the following is not a type of loss-of-function mutation?

A. conditional

B. hypomorphic

C. null

D. dominant-negative

E. ectopic

26. An unusual loss-of-function mutation that is not recessive is

A. null.

B. hypomorphic.

C. conditional.

D. dominant-negative.

27. A partial loss-of-function mutation is

A. null.

B. hypomorphic.

C. conditional.

D. dominant-negative.

28. What type of mutation is particularly useful to researchers who wish to study a genes effect on development when a natural loss-of function mutation has not yet been isolated?

A. haploinsufficient

B. hypomorphic

C. conditional

D. dominant-negative

29. What is the most significant advantage of using RNAi to study development?

A. Geneticists have only been able to identify a subset of the genes involved in development.

B. Genetic studies on a single gene can be completed without the creation or isolation of new mutant organisms.

C. RNA is easy to isolate.

D. RNAi causes phenotypes not typical of in vivo development.

30. RNAi

A. depletes protein products of genes.

B. uses dsRNA to trigger the degradation of mRNA.

C. is used to create a functional knock-out.

D. does all of the choices.

31. Results from RNAi studies are most likely to vary due to

A. varying amount of cellular uptake of dsDNA.

B. its nonheritable characteristic.

C. different levels of starting mRNA.

D. issues related to fertilization.

32. What technique would be used to best study a phenocopy?

A. RNAi

B. transgene

C. isolation of mutations

D. QTL mapping analysis

33. Mutations that result in a new phenotype for a gene through the production of too much protein are best described by the term

A. conditional.

B. permissive.

C. hypomorphic.

D. gain of function.

34. Gain-of-function alleles are usually

A. null.

B. conditional.

C. recessive.

D. dominant.

35. The expression of a gene at an abnormal place or time is called

A. epistasis.

B. ectopic.

C. epigenetic.

D. expressivity.

36. Gain-of-function mutations might involve which of the following?

A. deletion of a promoter region

B. constitutive activation of an enzyme

C. a synonymous mutation

D. None of the choices is correct.

37. What is the most common cause of rare spontaneous ectopic gene expression?

A. insertion mutation

B. deletion mutation

C. a mutation that moves the gene next to a new regulatory element

D. None of the choices is correct.

38. An example of ectopic gene expression is

A. achondroplastic dwarfism.

B. lack of eye development.

C. abnormal vulvar shape.

D. legs instead of antennae.

39. The presence of a homeodomain in a protein suggests what about its function?

A. It has kinase activity.

B. It is a membrane bound receptor.

C. It is a secreted protein.

D. It is a transcription factor.

40. What technique would you use to best determine when and in what cells of a given tissue a specific gene is expressed?

A. Northern analysis

B. in situ hybridization

C. RT-PCR

D. Southern analysis

41. How would you best follow the developmental timing of a given protein in vivo?

A. in situ hybridization

B. Western blotting

C. using a GFP-fusion protein transgenic organism

D. microarray analysis

42. What does a homeodomain do?

A. acts as a receptor

B. has kinase activity

C. It binds to specific DNA sequences

D. None of the choices is correct.

43. Screening for maternal-effect mutations would involve looking for which of the following?

A. unusual phenotypes in female progeny

B. embryos that are all obviously developmentally arrested

C. asymmetric mutations

D. eggs that can not be fertilized

44. In Drosophila, two maternal transcripts that are distributed evenly throughout the oocyte prior to fertilization are:

A. caudal and knirps

B. bicoid and nanos

C. caudal and hunchback

D. None of the choices is correct.

45. Which of the following is a zygotic gap gene in Drosophila?

A. knirps (kni)

B. even-skipped (eve)

C. caudal (cad)

D. hedgehog (hh)

E. None of the choices is zygotic genes.

46. Which of the choices gives the correct sequence of early embryonic development in Drosophila?

A. zygote, syncytial blastoderm, multinucleate syncytium, cellular blastoderm

B. zygote, cellular blastoderm, syncytial blastoderm, multinucleate syncytium.

C. zygote, multinucleate syncytium, syncytial blastoderm, cellular blastoderm.

D. These stages do not occur in Drosophila.

47. Cells that provide large amounts of mRNA and proteins for deposition into the egg are called

A. doctor cells.

B. nurse cells.

C. helper cells.

D. bicoid cells.

48. A molecule whose concentration determines the developmental fate of a cell is called

A. monomorphic.

B. a juxtacrine protein.

C. a signaling molecule.

D. a morphogen.

49. Signaling factors that complete cell-to-cell communication in the form of direct contact are called

A. juxtacrine factors.

B. paracrine factors.

C. endocrine factors.

D. All of the choices are correct.

50. Ligands that circulate throughout the body and signal developmental differentiation are called

A. juxtacrine factors.

B. paracrine factors.

C. endocrine factors.

D. All of the choices are correct.

51. A ligand secreted from a cell to a nearby cell that signals developmental differentiation is called

A. juxtacrine factor.

B. paracrine factor.

C. endocrine factor.

D. All of the choices are correct.

True / False Questions

52. A cloned organism will always be genotypically and phenotypically identical to the individual from which it was cloned.

True False

53. Although stem cells can continue dividing indefinitely, half of the cells they give rise to can differentiate into a variety of different cell types.

True False

54. Maternal and zygotic genes affect early development.

True False

55. Bicoid is a maternal-effect mutation that results in larvae with two heads.

True False

56. A nurse cell produces large amounts of mRNA and proteins for deposit into the Drosphila egg.

True False

57. Development requires progressive changes in gene expression.

True False

58. Developmental regulation occurs mostly at the level of mRNA stability.

True False

59. The green fluorescent protein gene is often joined to genes of interest thus producing a fusion protein that is easily followed in vivo.

True False

60. RNA in situ hybridization is an easier method of detecting gene regulation than by following the genes protein by immunohistochemistry.

True False

61. The homeodomain is a common DNA-binding domain in many transcription factors that regulate development.

True False

62. The sequence of early embryonic development in Drosophila is zygote, multinucleate syncytium, syncytial blastoderm, and cellular blastoderm.

True False

63. Bicoid is a maternal protein deposited in the anterior region of the egg in Drosophila.

True False

64. Maternal mRNA transcripts of the bicoid (bcd) gene are deposited in the anterior portion of the egg in Drosophila.

True False

65. One action of the Bicoid protein is to repress the translation of the caudal (cdl) transcripts.

True False

66. The maternal Nanos (nos) RNA transcript is the primary anterior morphogen in Drosophila zygote development.

True False

67. In Drosophila embryos, segment polarity genes operate prior to pair-rule genes.

True False

Essay Questions

68. How do cells which all contain identical genetic information differentiate into myriad cell types and ultimately undergo the miracle of development from an embryo into a child?

69. Model organisms are useful for the study of developmental genetics because significant ethical limitations restrict studies in humans. Discuss some taboos to research in humans.

70. What three characteristics of value to geneticists do model organisms share?

71. What advantages, in particular, do yeast provide with respect to the study of eukaryotes?

72. What properties of C. elegans make it a most useful model organism?

73. What gene controls eye development and to what degree is it evolutionarily conserved?

74. What gene controls eye development and to what degree is it evolutionarily conserved?

75. What is a dominant-negative mutation?

76. What is the molecular basis of haploinsufficiency?

77. You are a very lucky scientist. You observe that an interesting mutant phenotype has arisen in your cell culture. A clonal kidney cell line has what appears to be a patch of muscle cells growing in it. (This suggests that the cell began from a single mutant cell.) You wish to test the hypothesis that gene expression changes result in a change in morphology. How would you test your hypothesis?

78. Due to ethical considerations, development is studied in model organisms. How do you use genetic information gained from other species to isolate the human genes involved in development?

79. How can hypomorphic mutations help tease out pleiotropic effects in development?

80. What kind of mutation would be most helpful to test a hypothesis regarding the timing of developmental stages?

81. Describe the hierarchy of expression of zygotic genes in determining segmentation in Drosophila embryos.

82. You recover Drosophila embryos that instead of having a head region and tail region have two tail regions in mirror-image arrangement. Describe a maternal mutation that could cause this condition.

Chapter 18 Using Genetics to Study Development Key

Fill in the Blank Questions

1. Cells ________________ from each other during embryonic development to form hundreds of different cell types.

differentiate

Blooms Level: 1. Remember
Section: 18.01
Topic: Developmental Genetics

2. When a loss-of-function mutation results in a completely nonfunctional protein it is termed _________ mutation.

null

Blooms Level: 1. Remember
Section: 18.02
Topic: Developmental Genetics

3. When a loss-of-function mutation results in a partially nonfunctional protein it is termed _________ mutation.

hypomorphic

Blooms Level: 1. Remember
Section: 18.02
Topic: Developmental Genetics

4. When a loss-of-function mutation results in a nonfunctional protein under certain conditions (such as temperature) it is termed _________ mutation.

conditional

Blooms Level: 1. Remember
Section: 18.02
Topic: Developmental Genetics

5. When a loss-of-function mutation has a dominant effect it is termed________ _______ mutation.

dominant negative

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

6. An experimental strategy that uses dsRNA to deplete protein products in a cell is called ___________.

RNA inteference, RNAi

Blooms Level: 1. Remember
Section: 18.02
Topic: Developmental Genetics

7. __________________ gene expression is when a gene is expressed at an abnormal time or place.

Ectopic

Blooms Level: 1. Remember
Section: 18.02
Topic: Developmental Genetics

8. A ______________________ is a common motif in proteins with developmental significance.

homeodomain

Blooms Level: 1. Remember
Section: 18.03
Topic: Developmental Genetics

9. ________________ are genetic mosaics in which the cells of different genotypes come from two different individuals.

Chimeras

Blooms Level: 1. Remember
Section: 18.03
Topic: Developmental Genetics

10. A protein tagged with GFP is an example of a(n) _____________ protein.

fusion

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

11. Development requires progressive changes in _____________________.

gene expression

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

12. The anterior region of a Drosophila embryo is determined by the deposition of maternal ______________ transcripts.

bicoid, bcd

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

13. Embryos produced from mothers lacking a functional bicoid (bcd) gene do not develop ________________.

heads and thoraxes

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

14. Maternal hunchback (hb) mRNA transcripts are distributed _____________ in the egg prior to fertilization.

evenly

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

15. ____________________ are molecules whose concentration determines the developmental fate of a cell.

Morphogens

Blooms Level: 2. Understand
Section: 18.05
Topic: Developmental Genetics

Multiple Choice Questions

16. Which of the following is not one of the three characteristics of value to geneticists for model organisms?

A. ease of cultivation

B. rapid reproduction

C. small size

D. small genome

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

17. Which of the following is not a taboo on the use of humans in genetics studies?

A. phenotypic analysis

B. experimental manipulation of affected individuals

C. forced matings

D. deliberate production of mutants

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

18. Evolution has had what effect on development in various organisms?

A. varying

B. conservation of many genes and genetic pathways

C. removal of all mutations.

D. none

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

19. Mutations that disrupt the earliest stages of human development almost always cause

A. no effect.

B. polydactyly.

C. spontaneous abortion.

D. disruption of the segmented body plan.

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

20. Development occurs properly due to gene expression

A. at the right time.

B. in the right place.

C. in the right amount.

D. All of the choices are correct.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

21. If you wanted to study cellular lineage, which model organism would be best suited?

A. E. coli

B. S. cerevisiae

C. C. elegans

D. M. musculus

Blooms Level: 1. Remember
Section: 18.01
Topic: Developmental Genetics

22. Which of the following model organisms would be easiest to study recessive mutations using complementation analysis?

A. S. cerevisiae

B. C. elegans

C. M. musculus

Blooms Level: 1. Remember
Section: 18.01
Topic: Developmental Genetics

23. The Aniridia gene in humans is involved in eye formation. Although eye development is very different in flies, this gene is highly conserved. What is its homolog in Drosophila?

A. eyeless (ey)

B. Pax-6

C. noeye

D. ommatidia

Blooms Level: 1. Remember
Section: 18.01
Topic: Developmental Genetics

24. A loss-of-function mutation that depends on special circumstances is called

A. null.

B. hypomorphic.

C. conditional.

D. dominant-negative.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

25. Which of the following is not a type of loss-of-function mutation?

A. conditional

B. hypomorphic

C. null

D. dominant-negative

E. ectopic

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

26. An unusual loss-of-function mutation that is not recessive is

A. null.

B. hypomorphic.

C. conditional.

D. dominant-negative.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

27. A partial loss-of-function mutation is

A. null.

B. hypomorphic.

C. conditional.

D. dominant-negative.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

28. What type of mutation is particularly useful to researchers who wish to study a genes effect on development when a natural loss-of function mutation has not yet been isolated?

A. haploinsufficient

B. hypomorphic

C. conditional

D. dominant-negative

Blooms Level: 4. Analyze
Section: 18.02
Topic: Developmental Genetics

29. What is the most significant advantage of using RNAi to study development?

A. Geneticists have only been able to identify a subset of the genes involved in development.

B. Genetic studies on a single gene can be completed without the creation or isolation of new mutant organisms.

C. RNA is easy to isolate.

D. RNAi causes phenotypes not typical of in vivo development.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

30. RNAi

A. depletes protein products of genes.

B. uses dsRNA to trigger the degradation of mRNA.

C. is used to create a functional knock-out.

D. does all of the choices.

Blooms Level: 3. Apply
Section: 18.02
Topic: Developmental Genetics

31. Results from RNAi studies are most likely to vary due to

A. varying amount of cellular uptake of dsDNA.

B. its nonheritable characteristic.

C. different levels of starting mRNA.

D. issues related to fertilization.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

32. What technique would be used to best study a phenocopy?

A. RNAi

B. transgene

C. isolation of mutations

D. QTL mapping analysis

Blooms Level: 3. Apply
Section: 18.02
Topic: Developmental Genetics

33. Mutations that result in a new phenotype for a gene through the production of too much protein are best described by the term

A. conditional.

B. permissive.

C. hypomorphic.

D. gain of function.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

34. Gain-of-function alleles are usually

A. null.

B. conditional.

C. recessive.

D. dominant.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

35. The expression of a gene at an abnormal place or time is called

A. epistasis.

B. ectopic.

C. epigenetic.

D. expressivity.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

36. Gain-of-function mutations might involve which of the following?

A. deletion of a promoter region

B. constitutive activation of an enzyme

C. a synonymous mutation

D. None of the choices is correct.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

37. What is the most common cause of rare spontaneous ectopic gene expression?

A. insertion mutation

B. deletion mutation

C. a mutation that moves the gene next to a new regulatory element

D. None of the choices is correct.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

38. An example of ectopic gene expression is

A. achondroplastic dwarfism.

B. lack of eye development.

C. abnormal vulvar shape.

D. legs instead of antennae.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

39. The presence of a homeodomain in a protein suggests what about its function?

A. It has kinase activity.

B. It is a membrane bound receptor.

C. It is a secreted protein.

D. It is a transcription factor.

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

40. What technique would you use to best determine when and in what cells of a given tissue a specific gene is expressed?

A. Northern analysis

B. in situ hybridization

C. RT-PCR

D. Southern analysis

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

41. How would you best follow the developmental timing of a given protein in vivo?

A. in situ hybridization

B. Western blotting

C. using a GFP-fusion protein transgenic organism

D. microarray analysis

Blooms Level: 3. Apply
Section: 18.03
Topic: Developmental Genetics

42. What does a homeodomain do?

A. acts as a receptor

B. has kinase activity

C. It binds to specific DNA sequences

D. None of the choices is correct.

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

43. Screening for maternal-effect mutations would involve looking for which of the following?

A. unusual phenotypes in female progeny

B. embryos that are all obviously developmentally arrested

C. asymmetric mutations

D. eggs that can not be fertilized

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

44. In Drosophila, two maternal transcripts that are distributed evenly throughout the oocyte prior to fertilization are:

A. caudal and knirps

B. bicoid and nanos

C. caudal and hunchback

D. None of the choices is correct.

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

45. Which of the following is a zygotic gap gene in Drosophila?

A. knirps (kni)

B. even-skipped (eve)

C. caudal (cad)

D. hedgehog (hh)

E. None of the choices is zygotic genes.

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

46. Which of the choices gives the correct sequence of early embryonic development in Drosophila?

A. zygote, syncytial blastoderm, multinucleate syncytium, cellular blastoderm

B. zygote, cellular blastoderm, syncytial blastoderm, multinucleate syncytium.

C. zygote, multinucleate syncytium, syncytial blastoderm, cellular blastoderm.

D. These stages do not occur in Drosophila.

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

47. Cells that provide large amounts of mRNA and proteins for deposition into the egg are called

A. doctor cells.

B. nurse cells.

C. helper cells.

D. bicoid cells.

Blooms Level: 1. Remember
Section: 18.05
Topic: Developmental Genetics

48. A molecule whose concentration determines the developmental fate of a cell is called

A. monomorphic.

B. a juxtacrine protein.

C. a signaling molecule.

D. a morphogen.

Blooms Level: 1. Remember
Section: 18.05
Topic: Developmental Genetics

49. Signaling factors that complete cell-to-cell communication in the form of direct contact are called

A. juxtacrine factors.

B. paracrine factors.

C. endocrine factors.

D. All of the choices are correct.

Blooms Level: 1. Remember
Section: 18.05
Topic: Developmental Genetics

50. Ligands that circulate throughout the body and signal developmental differentiation are called

A. juxtacrine factors.

B. paracrine factors.

C. endocrine factors.

D. All of the choices are correct.

Blooms Level: 1. Remember
Section: 18.05
Topic: Developmental Genetics

51. A ligand secreted from a cell to a nearby cell that signals developmental differentiation is called

A. juxtacrine factor.

B. paracrine factor.

C. endocrine factor.

D. All of the choices are correct.

Blooms Level: 2. Understand
Section: 18.05
Topic: Developmental Genetics

True / False Questions

52. A cloned organism will always be genotypically and phenotypically identical to the individual from which it was cloned.

FALSE

Blooms Level: 2. Understand
Section: 18.05
Topic: Developmental Genetics

53. Although stem cells can continue dividing indefinitely, half of the cells they give rise to can differentiate into a variety of different cell types.

TRUE

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

54. Maternal and zygotic genes affect early development.

TRUE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

55. Bicoid is a maternal-effect mutation that results in larvae with two heads.

FALSE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

56. A nurse cell produces large amounts of mRNA and proteins for deposit into the Drosphila egg.

TRUE

Blooms Level: 2. Understand
Section: 18.05
Topic: Developmental Genetics

57. Development requires progressive changes in gene expression.

TRUE

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

58. Developmental regulation occurs mostly at the level of mRNA stability.

FALSE

Blooms Level: 1. Remember
Section: 18.03
Topic: Developmental Genetics

59. The green fluorescent protein gene is often joined to genes of interest thus producing a fusion protein that is easily followed in vivo.

TRUE

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

60. RNA in situ hybridization is an easier method of detecting gene regulation than by following the genes protein by immunohistochemistry.

FALSE

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

61. The homeodomain is a common DNA-binding domain in many transcription factors that regulate development.

TRUE

Blooms Level: 2. Understand
Section: 18.03
Topic: Developmental Genetics

62. The sequence of early embryonic development in Drosophila is zygote, multinucleate syncytium, syncytial blastoderm, and cellular blastoderm.

TRUE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

63. Bicoid is a maternal protein deposited in the anterior region of the egg in Drosophila.

FALSE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

64. Maternal mRNA transcripts of the bicoid (bcd) gene are deposited in the anterior portion of the egg in Drosophila.

TRUE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

65. One action of the Bicoid protein is to repress the translation of the caudal (cdl) transcripts.

TRUE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

66. The maternal Nanos (nos) RNA transcript is the primary anterior morphogen in Drosophila zygote development.

FALSE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

67. In Drosophila embryos, segment polarity genes operate prior to pair-rule genes.

FALSE

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

Essay Questions

68. How do cells which all contain identical genetic information differentiate into myriad cell types and ultimately undergo the miracle of development from an embryo into a child?

Gene regulation controls the timing, location, and amount of transcript necessary for cells to divide, change shape, specialize, and interact in highly reproducible ways.

Blooms Level: 3. Apply
Section: 18.05
Topic: Developmental Genetics

69. Model organisms are useful for the study of developmental genetics because significant ethical limitations restrict studies in humans. Discuss some taboos to research in humans.

Several aspects of research necessary to study development are unethical to complete in humans, such as the deliberate production of mutations, the experimental manipulation of affected individuals, and forced matings between individuals with various abnormalities.

Blooms Level: 3. Apply
Section: 18.01
Topic: Developmental Genetics

70. What three characteristics of value to geneticists do model organisms share?

Ease of cultivation, rapid reproduction, and small size.

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

71. What advantages, in particular, do yeast provide with respect to the study of eukaryotes?

Yeast are single celled eukaryotes having both haploid and diploid states, which make identification of mutations easier.

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

72. What properties of C. elegans make it a most useful model organism?

C. elegans is a transparent round worm with an invariant number of cells in the adult. The female is a hermaphrodite.

Blooms Level: 2. Understand
Section: 18.01
Topic: Developmental Genetics

73. What gene controls eye development and to what degree is it evolutionarily conserved?

The ey, Pax-6, and Aniridia genes control eye development in Drosophila, mice, and humans respectively. They are highly conserved, which is surprising given the distinct phenotypic differences in eyes between these organisms.

Blooms Level: 3. Apply
Section: 18.03
Topic: Developmental Genetics

74. What gene controls eye development and to what degree is it evolutionarily conserved?

The ey, Pax-6, and Aniridia genes control eye development in Drosophila, mice, and humans respectively. They are highly conserved, which is surprising given the distinct phenotypic differences in eyes between these organisms.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

75. What is a dominant-negative mutation?

A dominant negative mutation is one where the loss of function is dominant rather than recessive, as is usual for loss-of-function mutations.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

76. What is the molecular basis of haploinsufficiency?

The molecular basis of haploinsufficiency is that one wild-type allele does not produce sufficient protein to function and show the wild-type phenotype.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

77. You are a very lucky scientist. You observe that an interesting mutant phenotype has arisen in your cell culture. A clonal kidney cell line has what appears to be a patch of muscle cells growing in it. (This suggests that the cell began from a single mutant cell.) You wish to test the hypothesis that gene expression changes result in a change in morphology. How would you test your hypothesis?

To test the hypothesis that gene expression changes are involved in the muscle phenotype, you could carefully isolate the dividing cells of both phenotypes and complete a microarray analysis. Most labs now have access to a reasonably complete clone set of human genes. Hybridization of cDNA from the two cell types mRNA against each other would identify differences and generate new hypotheses regarding developmental differentiation. Control muscle cells versus the newly formed muscle cells would need to be included in your experiment in order to identify the difference between genes giving rise to muscle cells and genes that maintain the muscle cell phenotype.

Blooms Level: 5. Evaluate
Section: 18.02
Topic: Developmental Genetics

78. Due to ethical considerations, development is studied in model organisms. How do you use genetic information gained from other species to isolate the human genes involved in development?

You can use genes cloned in other organisms to find homologs in the human genome. This has been made considerably easier with the publication of the human genome sequence.

Blooms Level: 2. Understand
Section: 18.02
Topic: Developmental Genetics

79. How can hypomorphic mutations help tease out pleiotropic effects in development?

Since hypomorphic mutations are a partial loss of function, they often allow survival of a homozygous lethal mutation and pleiotropic effects are uncovered.

Blooms Level: 3. Apply
Section: 18.02
Topic: Developmental Genetics

80. What kind of mutation would be most helpful to test a hypothesis regarding the timing of developmental stages?

When testing the effects of a protein on developmental timing, it is often beneficial to isolate conditional mutants so that the gene can be turned off and turned on by utilizing conditions that are specifically restrictive and permissive.

Blooms Level: 3. Apply
Section: 18.02
Topic: Developmental Genetics

81. Describe the hierarchy of expression of zygotic genes in determining segmentation in Drosophila embryos.

The hierarchical sequence is gap genes, followed by pair-rule genes, and finally segment polarity genes.

Blooms Level: 2. Understand
Section: 18.04
Topic: Developmental Genetics

82. You recover Drosophila embryos that instead of having a head region and tail region have two tail regions in mirror-image arrangement. Describe a maternal mutation that could cause this condition.

If the female parent is homozygous for a loss-of-function mutation to bicoid (bcd), the embryos she produces will be unable to produce the Bicoid protein. Therefore, they cannot develop head and thorax regions, and they also cannot repress translation of the maternal caudal (cad) gene, which governs development of the tail region.

Blooms Level: 5. Evaluate
Section: 18.04
Topic: Developmental Genetics

Chapter 18 Using Genetics to Study Development Summary

Category # of Questions
Blooms Level: 1. Remember 16
Blooms Level: 2. Understand 55
Blooms Level: 3. Apply 8
Blooms Level: 4. Analyze 1
Blooms Level: 5. Evaluate 2
Section: 18.01 12
Section: 18.02 30
Section: 18.03 14
Section: 18.04 17
Section: 18.05 9
Topic: Developmental Genetics 82

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