Question 1

It is presently believed that the asymmetric distribution of substances in the egg,positioned by the mother,is responsible for establishing the determined state.Which general term describes such molecular positioning?

Accepted Answer

The answer of It is presently believed that the asymmetric...

Question 2

A gene that specifies the fate of a particular anatomical segment in Drosophila is called a(n)________.

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The answer of A gene that specifies the fate of...

Question 3

Which class of genes controls the developmental identity of segments along the anterior-posterior axis?

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The answer of Which class of genes controls the developmental...

Question 4

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

Accepted Answer

A homeobox gene is a type of regulatory gene that produces a specific DNA sequence, known as a homeodomain, which is involved in the development of an organism's body plan. Homeobox genes do not produce repetitive base sequences like VNTRs.

Question 5

Differentiation is the process whereby a cell's determined state is expressed.

Accepted Answer

Differentiation is indeed the process whereby a cell's determined state is expressed.

Question 6

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

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The answer of Do Hox gene clusters exist in humans?...

Question 7

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?

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The answer of Molecular/structural orientations (gradients)in an egg are thought...

Question 8

Drosophila and Arabidopsis use different sets of nonhomologous master regulatory genes to establish the body axis and specify the identity of structures along such an axis.

Accepted Answer

Drosophila and Arabidopsis are two different organisms with distinct genetic and developmental mechanisms. While both rely on master regulatory genes to establish the body axis and specify structures along it, these master regulatory genes are not homologous between the two species, meaning that they do not share a common evolutionary origin. Therefore, they use different sets of nonhomologous master regulatory genes to achieve these developmental outcomes.

Question 9

Genetic involvement in development appears to be achieved,at least in part,by variable gene activity.

Accepted Answer

Genetic involvement in development is achieved through variable gene activity, meaning certain genes are turned on or off at specific times and in specific tissues during development, leading to differentiation and the formation of specific structures and organs in the body.

Question 10

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

Accepted Answer

Determination is indeed the process by which a cell's fate is decided, whether it will become a neuron, muscle cell, or any other type of specialized cell.

Question 11

From a human developmental standpoint,what is the significance of Hox genes?

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The answer of From a human developmental standpoint,what is the...

Question 12

During development,many genes act in such a way as to decrease the number of alternative developmental pathways that a cell can follow.Usually there are two alternative developmental paths for a cell to follow.What is the term given to genes that act in this fashion?

Accepted Answer

The answer of During development,many genes act in such a...

Question 13

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

Accepted Answer

Maternal-effect genes are known to play a crucial role in determining the anterior-posterior axis during embryonic development in Drosophila. These genes are expressed in the female germline and contribute to the patterning of the embryo before the zygotic genes become active.

Question 14

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?

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Question 15

What is the general order of genes involved in determining early Drosophila development?

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Question 16

The bicoid gene of Drosophila generates embryos with two posterior regions.What is the likely aspect of embryonic development that the bicoid gene probably controls?

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Question 17

Give a brief definition of a homeobox.

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Question 18

What significant conclusion has the classic work on the eyeless and Pax6 genes provided in terms of developmental mechanisms?

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Question 19

What is the significance of the homeodomain?

Accepted Answer

The answer of What is the significance of the homeodomain?...

Question 20

Segmentation genes,such as the pair-rule class,are inherited through mitochondrial DNA in Drosophila.

Accepted Answer

Segmentation genes, including the pair-rule class, are inherited through nuclear DNA in Drosophila, not mitochondrial DNA. Mitochondrial DNA is only inherited maternally and is responsible for encoding proteins involved in oxidative phosphorylation.

Quiz 18: Developmental Genetics