Question 1

A homeobox gene is one that produces a group of repetitive base sequences such as a VNTR.

Accepted Answer

A) True 
 B)False  False

Question 2

Experiments involving nuclear transplantation in amphibians indicate that nuclei derived from blastula are more likely to support development of complete and normal adults compared with those derived from later stages of development.What do these experiments tell us about the process of development?

Accepted Answer

Development occurs as a series of cascades,with early genes influencing late genes,at times with stability.Such progressive determination,if stable,may be irreversible and fail to support development of an entire organism from a single cell.A number of epigenetic factors such as chromatin remodeling and DNA methylation are also likely to come into play.

Question 3

It is often said that development is a two-step process.Which two steps are likely to be referred to here?

Accepted Answer

determination and differentiation

Question 4

In Drosophila,maternal-effect genes are influential in determining the anterior-posterior organization of the developing embryo.

Accepted Answer

A) True 
 B)False

Question 5

Which term refers to the regulatory events that establish a specific pattern of gene activity and developmental fate for a given cell?

Accepted Answer

A)  lysogen
B)  differentiation
C)  determination
D)  gradient regulated
E)  attenuation

Question 6

Design an experiment that would allow you to determine if a particular nucleus in a Drosophila embryo is capable of directing development of an entire new fly.

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Question 7

How do segment polarity genes relate to pair-rule genes?

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Question 8

Define determination and differentiation.

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Question 9

Molecular/structural orientations (gradients)in an egg are thought to play a significant role in development.What is the origin of such gradients? What evidence indicates that the maternal genotype is involved in providing such gradients?

Accepted Answer

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Question 10

Mutations that eliminate a contiguous region in the Drosophila embryo's segmentation pattern are called ________.

Accepted Answer

A)  homeodomains
B)  gap genes
C)  compartment genes
D)  linkage genes
E)  segment genes

Question 11

In Drosophila,what is the order of function of the segmentation genes?

Accepted Answer

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Question 12

Determination is the process whereby a cell's eventual developmental fate is set.

Accepted Answer

A) True 
 B)False

Question 13

Maternal effects are cases of extrachromosomal inheritance in which the genotype of the mother influences the phenotype of her immediate offspring in a non-Mendelian manner.Provide a rationale for the molecular basis of a maternal effect.

Accepted Answer

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Question 14

What kinds of general observations cause one to conclude that development is the result of variable gene activity?

Accepted Answer

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Question 15

Provide a brief description of segment polarity genes,including their regulation and their molecular and developmental effects.

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Question 16

Do Hox gene clusters exist in humans? If so,how many are known to exist?

Accepted Answer

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Question 17

Mutations in the selector genes sometimes form structures in the wrong segment,transforming the antenna of a fly into a leg,for example.What are such mutations called?

Accepted Answer

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Question 18

Give a brief definition of a homeobox.

Accepted Answer

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Question 19

The bicoid gene of Drosophila generates embryos with two posterior regions.What aspect embryonic development does the bicoid gene control?

Accepted Answer

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Question 20

Explain the differences between differentiation and determination.Provide examples of each process and indicate how each is involved in development.

Accepted Answer

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Exam 20: Developmental Genetics