Deck 20: The Genetic Control Of Animal Development

Question 1

Which of the following types of cells gives rise to germ line cells in Drosophila?

A) Pole cells
B) Cellular blastoderm cells
C) Chorion cells
D) Micropyle cells
E) None of these are correct.

Answer 1

A

Question 2

Which of the following organisms are considered to be premier model organisms for the genetic analysis of animal development?

A) Drosophila
B) C. elegans
C) Chickens
D) Drosophila and C. elegans
E) All of these are correct.

Answer 2

E

Question 3

During Drosophila development,each egg is surrounded by a tough shell-like structure that is made of materials synthesized by somatic cells in the ovary.This structure is called the

A) micropyle.
B) chorion.
C) syncytium.
D) cellular blastoderm.
E) imaginal disc.

Answer 3

B

Question 4

Which statement is false with regard to development in C.elegans?

A) Hermaphrodites have two X chromosomes and five autosomes.
B) XO animals can be crossed with XX hermaphrodites.
C) It is possible to trace the lineage of all of the cells in the adult from the zygote.
D) All adult tissue arises from six founder cells.
E) Self-incompatibility ensures that sperm cannot fertilize eggs from the same animal.

Question 5

The system to ascertain the X:A ratio involves interactions between which of the following?

A) Maternally synthesized proteins that have been deposited in the egg cytoplasm, and embryonically synthesized proteins that are encoded by several X-linked genes
B) Embryonically synthesized proteins that have been deposited in the egg cytoplasm and maternally synthesized proteins that are encoded by several X-linked genes
C) Paternally synthesized proteins that have been deposited in the sperm cytoplasm and embryonically synthesized proteins that are encoded by several X-linked genes
D) Embryonically synthesized proteins that have been deposited in the sperm cytoplasm and paternally synthesized proteins that are encoded by several Y-linked genes
E) None of these are correct.

Question 6

Why were frogs and sea urchins typically used to study development in classical anatomy and embryology?
1)The eggs developed outside of the mother.
2)The eggs were easily manipulated.
3)The animals were easy to breed.

A) 1
B) 2
C) 3
D) 1 and 2
E) All of these are correct.

Question 7

The term "syncytium" refers to which of the following stages of Drosophila development?

A) A single layer of cells on the embryo's surface
B) A worm-like structure that hatches by chewing through the egg shell
C) A single cell with many identical nuclei
D) An immobile structure with a hard skin
E) An adult insect

Question 8

In Drosophila a single layer of cells on the embryo's surface,which will give rise to all somatic tissues in the organism is known as

A) micropyle.
B) chorion.
C) syncytium.
D) cellular blastoderm.
E) imaginal disc.

Question 9

What is encoded by the somatic sex-determination pathway in Drosophila?

A) Proteins that regulate RNA splicing
B) Signaling molecules
C) Signaling receptors
D) Signaling transcription factors
E) All of these are correct.

Question 10

Which of the following is not a reason why C.elegans is an excellent model system for studying development?

A) The animal has a life cycle that is completed in three days.
B) It is a hermaphrodite species.
C) It is a transparent animal.
D) It has invariant cell lineages that form tissue of the adult.
E) XO mutants produced by meiotic disjunction are sterile.

Question 11

Which of the following is the master regulator of the Drosophila sex-determination pathway?

A) Numerator elements
B) Denominator elements
C) Transformer gene
D) Sex-lethal gene
E) Doublesex gene

Question 12

How many "founder" cells are produced by the series of asymmetric cell divisions in C.elegans?

A) 1
B) 2
C) 4
D) 6
E) 8

Question 13

Which of the following signals is used in the sex determination pathway in both Drosophila and C.elegans.

A) Number of X chromosomes
B) Number of Y chromosomes
C) Ratio of X and Y chromosomes
D) Ratio of X chromosomes to autosomes
E) Number of autosomes

Question 14

Which of the following methods can be used to identify genes that are involved in important developmental events?

A) Collect mutations and test for allelism
B) RT-PCR
C) Fluorescent labeling
D) RNA and protein blotting
E) All of these are correct.

Question 15

In Drosophila with two X chromosomes and three pairs of autosomes (genotype XX; AAA),how do flies develop?

A) They become males.
B) They become females.
C) They become intersex flies.
D) They do not develop as this is lethal.
E) They become hermaphrodites.

Question 16

Which of the following is a gene product that can participate in a developmental pathway?

A) Signal molecules
B) Signal receptors
C) Signal transducers
D) Transcription factors
E) All of these are correct.

Question 17

Which of the following can be used to study developmental pathways?
1)Identifying genes whose products are involved in the differentiation of specific phenotypes
2)Identifying genes whose products are involved in the dedifferentiation of genotypes
3)Identifying proteins whose products are not involved in the differentiation of specific phenotypes

A) 1
B) 2
C) 3
D) 1 and 3
E) All of these are correct.

Question 18

What is encoded by the somatic sex determination pathway in C.elegans?
1)Proteins that regulate RNA splicing
2)Signaling molecules
3)Signaling receptors

A) 1
B) 2
C) 3
D) 1 and 2
E) 2 and 3

Question 19

Which of the following is true regarding the model organism C.elegans?

A) C. elegans completes its life cycle in three days.
B) C. elegans is a hermaphroditic species.
C) Self fertilization is possible.
D) All of these are true.
E) None of these are true.

Question 20

Which statement does not apply to sex determination in Drosophila?

A) Sxl gene is turned on early in development only in XX embryos.
B) Sxl gene is never turned on in XY embryos.
C) Sxl gene is the master regulator of sex determination in Drosophila.
D) SXL protein is a regulator of splicing of Sxl transcripts.
E) Sxl transcript can be differentially spliced.

Question 21

Recessive mutations in maternal-effect genes are expressed only in embryos produced by

A) females homozygous for the mutation.
B) females heterozygous for the mutation.
C) males homozygous for the mutation.
D) males heterozygous for the mutation.
E) None of these are correct.

Question 22

Which of the following statements best characterizes a homeotic gene?

A) They define segmental regions in the embryo.
B) They define the anterior and posterior compartments of individual segments.
C) Mutations in these genes cause one body part to look like another.
D) They are responsible for sex determination.
E) They are involved in gene dosage compensation.

Question 23

Geneticists can study development in vertebrates by:
1)Applying knowledge gained from the study of model invertebrates
2)Analyzing mutations and phenocopies of mutant genes in model vertebrates such as mice and zebrafish
3)Examining the differentiation of stem cells

A) 1
B) 2
C) 3
D) 1 and 2
E) All of these are correct.

Question 24

Which of the following is another name for selector genes?

A) Homeotic genes
B) Segmentation genes
C) Gap genes
D) Pair-rule genes
E) Segment-polarity genes

Question 25

A mutation that causes one body part to look like another is known as a(n)

A) automutation.
B) homeotic mutation.
C) heteromic mutation.
D) xenotic mutation.
E) bithorax mutation.

Question 26

In C.elegans loss-of-function mutations in the two transformer genes tra-1 and tra-2 cause XX animals

A) to develop as normal females.
B) to develop as males.
C) to develop as hermaphrodites.
D) to develop as intersex individuals.
E) None of these are correct.

Question 27

Which of the following is an example of colinearity?

A) Replacement of a normal allele by a mutated transgene
B) Migration of cells during embryogenesis to form three primary germ layers
C) A process in which cells are assigned developmental fates
D) The physical order of genes corresponding to their expression along the anterior-posterior axis
E) Genetic dissection of a developmental pathway by analyzing gene mutations

Question 28

Which of the following is a large cluster of homeotic genes?
1)Bithorax complex
2)Antennapedia complex
3)Fermurtibia complex

A) 1
B) 2
C) 3
D) 1 and 2
E) 2 and 3

Question 29

Which of the following genes is a maternal-effect gene in Drosophila?

A) Dorsal
B) Bicoid
C) Nanos
D) All of these are correct.
E) None of these are correct.

Question 30

The identity of each body segment in Drosophila is determined by the products of genes in which of the following complexes?

A) Bithorax
B) Antennapedia
C) Femurtibia
D) Bithorax and antennapedia
E) Antennapedia and femurtibia

Question 31

The process of determining the fate of an undifferentiated cell using a signal from a differentiated cell is known as

A) deduction.
B) induction.
C) repression.
D) inhibition.
E) None of these are correct.

Question 32

How is a chimeric mouse characterized?

A) A combination of XX and XY cells
B) An intersex phenotype
C) A mouse with abnormal body morphology as a result of gene mutations
D) A mouse with a homozygous recessive mutation in a gene
E) A mouse with a mixture of its own and cultured ES cells

Question 33

The following mutations would result in phenotypic males except for loss-of-function mutations in

A) the transformer gene.
B) the transformer2 gene.
C) Sxl in XY animals.
D) Dsx in XX animals.
E) Sxl in XX animals.

Question 34

Which of the following is a segmentation gene discovered along the anterior-posterior axis?

A) Gap genes
B) Pair-rule genes
C) Segment polarity genes
D) Gap genes and Pair-rule genes
E) All of these are correct.

Question 35

Which of the following mutations were used to study the genetic control of anatomically correct organ formation?

A) Eyeless
B) Wingless
C) Hunchback
D) Nanos
E) Bithorax

Question 36

Translation of the Sxl mRNA in XY embryos results in

A) functional SXL protein.
B) a polypeptide without regulatory functions.
C) synthesis of functional transformer protein.
D) repression of the genes required for male development.
E) repression of the genes required for female development.

Question 37

What is the phenotype of homozygous,loss-of-function mutations in the Sxl gene in XY animals?

A) They develop into normal males.
B) They develop into males, but the mutation is lethal.
C) They develop into normal females.
D) They develop into females, but the mutation is lethal.
E) The animals develop as intersexes.

Question 38

Maternal-effect gene products are involved in:
1)Dorsal-ventral axes determination in Drosophila
2)Anterior-posterior axes determination in Drosophila
3)Dorsal-ventral axes determination in C.elegans

A) 1
B) 2
C) 3
D) 1 and 2
E) 2 and 3

Question 39

Which of the following genes is involved in sex-determination and in dosage compensation in Drosophila?

A) Numerator elements
B) Denominator elements
C) Sxl gene
D) Transformer gene
E) Doublesex gene

Question 40

Mutations in genes that contribute to the formation of healthy eggs may have no effect on the viability or appearance of the female making those eggs.These are known as

A) maternal effect mutations.
B) paternal effect mutations.
C) maternal gene mutations.
D) maternal offspring mutations.
E) embryo mutations.

Question 41

Which statement is false concerning zebra fish?

A) Morpholinos are used to block the translation of specific transcripts.
B) Morpholinos do not act over a very long period of time after injection into fertilized eggs.
C) Its genome is 1.5 billion bp in length and contains 22,000 known and predicted genes.
D) Zebra fish have become a model genetic organism for vertebrates.
E) None of these

Question 42

An insertion that is specifically targeted to a gene,disrupting the integrity of that gene is known as

A) knockdown.
B) knockout.
C) cutout.
D) positive deletion.
E) negative deletion.

Question 43

Discuss some of the ethical implications that surround the study stem cells in the genetic analysis of development in vertebrates.

Question 44

What are the basic steps in constructing a knockout mutation in mice?

Question 45

What are maternal-effect genes and how can they be identified?

Question 46

When genes are transcribed in the same direction,with expression proceeding from one end of a cluster to the other end,both spatially (anterior to posterior in the embryo)and temporally (early to late in development)it is known as

A) bilinearity.
B) colinearity.
C) homologous transcription.
D) heterolinearity.
E) homolinearity.

Question 47

Why is C.elegans an excellent model system to study development?

Question 48

Therapeutic cloning

A) involves producing ES cells by injecting a somatic cell nucleus into an enucleated egg.
B) is the same as reproductive cloning.
C) involves producing individuals from ES cell nuclei injected into an enucleated egg.
D) All of these are correct.
E) None of these are correct.

Question 49

Explain how the developmental signal controls sex determination in Drosophila?

Question 50

Which of the following is a vertebrate homologue of the homeotic genes in Drosophila? A)Hox genes
B)Tra genes
C)Dsx genes
D)Sxl genes
E)None of these are correct.