Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMS2042 > Developmental Genetics > Flashcards

Developmental Genetics Flashcards

1
Q

How many segments correspond to pair-rule genes in Drosophila?

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Definition

a structure that forms from the ectodermal cells at the distal end of each limb bud and acts as a major signaling center to ensure proper development of a limb

A

Apical Ectodermal Ridge (AER)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the features of 46, XY DSD atypical gonad formation?

A

Abnormal gonads:

  • Streak gonads of fibrous tissue (dysgenesis)
  • Female ducts and variable female external genitalia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the characteristics of Hox genes expressed towards the 5’ end of the DNA?

A

They are expressed more posterior later in development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Definition

a protein that creates a posterior-to-anterior slope and is a morphogen that helps in abdomen formation

A

Nanos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the features of 46, XX DSD atypical gonad formation?

A

Abnormal gonads:

  • Testicular or partially testicular gonads
  • Male external genitalia
  • Infertility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

True or False:

Specification is irreversible fate commitment

A

False

Specification is flexible; cells can still be influenced by extrinsic factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define

Transcription factor

A

a DNA-binding protein that bonds to specific sequences adjacent to or within the promotor region of a gene; regulates gene transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the gene hierarchy of a Drosophila body plan?

A
  1. Maternal effect genes
  2. Gap genes
  3. Pair-rule genes
  4. Segment polarity genes
  5. Homeotic selector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What signalling molecule is secreted by dorsal ectoderm?

A

Wnt7a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Definition

a family of cell signalling proteins that are involved in a wide variety of processes, most notably as crucial elements for normal development

A

Fibroblast growth factor (Fgf)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do gap and pair-rule genes encode?

A

Transcription factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What interacts with the AER to regulate proximal-distal patterning?

A

Mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Definition

a mutation that causes a tissue normally determined to form a specific organ or body part to alter its pathway of differentiation and form another structure

A

Homeotic transformations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define

Segment polarity genes

A

genes that regulate the spatial pattern of differentiation within each segment of the developing Drosophila embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Definition

genes expressed as stripes around the blastoderm embryo during development of the Drosophila embryo

A

Pair-rule genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Definition

a DNA-binding protein that bonds to specific sequences adjacent to or within the promotor region of a gene; regulates gene transcription

A

Transcription factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Definition

each of a number of body segments containing the same internal structures, clearly visible in invertebrates such as earthworms but also present in the embryonic stages of vertebrates

A

Somite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Definition

A growth factor important and necessary for setting up and maintaining the midbrain/hindbrain border which plays the vital role of “organizer” in development

A

Fgf8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which genes are required for ovary development?

A

R-SPO1

WNT4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

True or False

Sox gene products interact with DNA similar to Hox gene products

A

True

Except they bind to the minor groove instead of the major groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define

Homeodomain

A

part of the protein that attaches (binds) to specific regulatory regions of the target genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Define

Organogenesis

A

the production and development of the organs of an animal or plant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What do homeotic selector genes do?

A

Specify the characteristic structures of each segment (i.e. thorax with legs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Definition

medical conditions involving the development of the reproductive system

A

Disorders of Sex Development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What commonly happens to the SRY gene 46, XY feminised patients?

A

It gets deleted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the name given to a gene that influences more than one developmental process/phenotypic trait?

A

Pleiotropic gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Define

Determination

A

establishment of a specific pattern of gene activity and developmental fate for a given cell, usually prior to any manifestation of the cell’s future phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Definition

a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors

A

Wnt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Define

Autopod

A

The distal major subdivision of a limb (hand or foot)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How do limb buds form?

A

Mesenchymal cells migrate out to form a bulge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Define

Somite

A

each of a number of body segments containing the same internal structures, clearly visible in invertebrates such as earthworms but also present in the embryonic stages of vertebrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Define

Fgf8

A

A growth factor important and necessary for setting up and maintaining the midbrain/hindbrain border which plays the vital role of “organizer” in development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Definition

the production and development of the organs of an animal or plant

A

Organogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What do the Wolffian ducts become in males?

A

Nothing, they regress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Definition

A section of an animal’s limb corresponding to the forearm.

A

Zeugopod

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Definition

genes that regulate the spatial pattern of differentiation within each segment of the developing Drosophila embryo

A

Segment polarity genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Define

Stylopod

A

the upper part of the arm in limb development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

In Drosophila, which important molecules are encoded by segment polarity genes?

A

Wingless and Hedgehog

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Define

Bone Morphogenetic Protein (BMP)

A

a group of growth factors also known as cytokines considered to constitute a group of pivotal morphogenetic signals, orchestrating tissue architecture throughout the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Define

Segmentation genes

A

a gene involved in the early stages of pattern formation that define repeated units (metameres) in a segmented organism, usually the embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the two main maternal mRNAs that set up anterior-posterior axis in Drosophila?

A

Bicoid and nanos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Cells that spend the most time in the progress have a more _______ fate

A

distal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Define

Hunchback

A

a gene required for segmentation of an anterior and posterior region of the Drosophila embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Where would you expect to find seminiferous cords?

a. The undifferentiated gonad
b. The developing testis
c. The developing ovary
d. Sertoli cells

A

b. The developing testis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Define

Colinearity

A

the linear relationship between the nucleotide sequence in a gene (or the RNA transcribed from it) and the order of amino acids in the polypeptide chain specified by the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Define

Homeobox

A

a sequence of 180 nucleotides that encodes a sequence of 60 amino acids called a homeodomain, which is part of a DNA-binding protein that acts as a transcription factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Definition

a gene required for segmentation of an anterior and posterior region of the Drosophila embryo

A

Hunchback

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

True or False:

Hox genes are expressed in discrete domains along the A-P axis

A

False

They are expressed in overlapping domains, with each area having a unique combination of Hox gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Low concentrations of Shh leads to a more __________ development

A

Anterior (i.e. thumb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What does R-SPO1 mutations cause in humans?

A

XX male development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Define

Gap genes

A

genes expressed in contiguous domains along the anterior-posterior axis of the Drosophila embryo that regulate the process of segmentation in each domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Complete this image

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Nano protein ________ translation of caudal mRNA and ________ hunchback

A

Does not effect; represses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What do mutants of homeotic genes cause?

A

Homeotic transformations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is the most common cause of 46, XY DSD?

A

Partial or complete androgen insensitivity syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

How does SRY affect R-spo1?

A

SRY inhibits the inhibitory effects of R-spo1 allowing male development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Define

Morphogenesis

A

the biological process that causes an organism to develop its shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What are the features of 46, XX DSD abnormal testosterone action?

A
  • Increased androgen action (e.g. increased testosterone in Congenital Adrenal Hyperplasia)
  • Gonads normal ovaries but external genitalia and masculinised
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

How many Hox clusters do Drosophila have?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is the fate of the Müllerian ducts in an XY embryo?

a. They are stimulated by testosterone
b. They become vas deferens and epididimys
c. They regress and disappear
d. They form the Fallopian tubes and uterus

A

c. They regress and disappear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Which human digit develops due to high concentrations of Shh?

A

Pinky

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Define

Homeotic selector (Hox) genes

A

genes that confer segment identity in Drosophila. They encode homeodomain proteins which interact with Hox and other homeotic genes to initiate segment-specific gene regulation. Homeodomain proteins are transcription factors that share a DNA-binding domain called the homeodomain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What is the human ortholog of wingless?

A

Wnt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

How many categories are there in the Prader scale?

A

Seven

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Which models are used to study limb morphogenesis?

A

Mouse and chicken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What type of genes set up anterior-posterior polarity in Drosophila?

A

Maternal effect genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What commonly happens to the SRY gene in 46, XX masculinised patients?

A

Aberrant translocation onto the X chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What controls the anterior-posterior axis of the limb?

A

Zone of polarising activity (ZPA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Definition

a secreted growth factor that acts in a paracrine fashion to reinforce the cell-autonomous activities of the transcription factors SRY and SOX9

A

Fgf9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Label this image of the limb bud

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

The organisation of tissues (ecto-, meso- or endoderm-derived) into organs is collectively known as what?

A

Organogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What type of cell does Wnt4 and R-spo1 expression occur in females?

A

Granulosa cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What do transgenic XX mice carrying the SRY gene develop into?

A

Male mice with testes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Label this image

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What is massively parallel sequencing (MPS)?

A

A technique where the whole genome is sequenced and compared to parental samples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Define

Sox9

A

a transcription factor that plays a pivotal role in male sexual development by producing a hormone in the Sertoli cells to inhibit the creation of a female reproductive system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

How do BMPs control the ventral development of a limb?

A

BMPs activate Engrailed in the ventral ectoderm which represses Wnt7a leading to ventral development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Definition

the upper part of the arm in limb development

A

Stylopod

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Definition

genes expressed in contiguous domains along the anterior-posterior axis of the Drosophila embryo that regulate the process of segmentation in each domain

A

Gap genes

84
Q

Label this image

A
85
Q

Label the following image of segment polarity gene action

A
86
Q

Supporting cells in the male embryo become what?

A

Sertoli cells of seminiferous cords

87
Q

Complete this image

A
88
Q

Definition

The distal major subdivision of a limb (hand or foot)

A

Autopod

89
Q

Define

Pleiotropy

A

condition in which a single mutation causes multiple phenotypic effects

90
Q

What causes cells to commit to a fate?

A

Cell-cell signalling

91
Q

A subset of _________ gene series is involved in anterior-posterior patterning

A

Hoxd

92
Q
A
93
Q

Is hunchback a maternal effect or a gap gene?

A

Gap gene

94
Q

Label this image

A
95
Q

Definition

the developmental process by which cells acquire different identities, depending on their relative spatial positions within the embryo

A

Pattern formation

96
Q

Germ cells in a male embryo become what?

A

Spermatozoa

97
Q

What does the two signal model of limb development propose?

A

Proximal-distal patterning is controlled by the concentration gradients of retinoic acids and Fgfs. The higher the concentration of retinoic acid, the more proximal the cells. The higher the concentration of Fgfs, the more distal they become

98
Q

Define

Paralog

A

Two or more genes in the same species derived from duplication and subsequent divergence from a single ancestral gene

99
Q

How does the R-spondin1 gene impact the β-catenin pathway leading to ovary development?

A

R-SPO1 stabilizes β-catenin, leading to target gene activation which results in ovary development

100
Q

Why is bicoid called a “maternal effect gene?

a. It is made by the mother fly during egg production
b. It is deleted in female flies when the fly reproduces
c. It only has effects in female flies
d. The effects are only seen in the mother fly’s body

A

a. It is made by the mother fly during egg production

101
Q

Ambiguous genitalia are detected at birth, how is this individual diagnosed?

A
  • Sex chromosome karyotype: XX or XY
  • Serum hormone measurements
  • Examination of external genitalia and ultrasound of internal gonads
102
Q

Which maternal mRNA sets up the anterior end of Drosophila embryo?

A

Bicoid

103
Q

How are the 7 segments of the Drosophila turned into 14?

A

Segment polarity genes encode wingless and hedgehog. One row of cells express wingless and one row expresses hedgehog creating 14 segments

104
Q

Definition

a sequence of 180 nucleotides that encodes a sequence of 60 amino acids called a homeodomain, which is part of a DNA-binding protein that acts as a transcription factor

A

Homeobox

105
Q

Label this image

A
106
Q

Which homeobox transcription factor is involved in dorsal development of the limb? How is it activated?

A

Lim1 - activated by the expression of Wnt7a in dorsal ectoderm

107
Q

Define

Fgf9

A

a secreted growth factor that acts in a paracrine fashion to reinforce the cell-autonomous activities of the transcription factors SRY and SOX9

108
Q

Definition

part of the protein that attaches (binds) to specific regulatory regions of the target genes

A

Homeodomain

109
Q

Definition

Two or more genes in the same species derived from duplication and subsequent divergence from a single ancestral gene

A

Paralog

110
Q

True or False:

R-SPO1, as well as Wnt4, binds to the Frizzled receptor, activating β-catenin

A

True

111
Q

46, XX DSD can be explained by ______-of-function of R-spo1/Wnt4 or ______-of-function of SRY/Sox9

A

Loss; gain

112
Q

Which human digit develops due to low Shh concetrations?

A

Thumb

113
Q

Definition

a maternal effect genes that are important in the formation of more posterior abdominal segments of the Drosophila embryo

A

Caudal (gene)

114
Q

Define

Engrailed

A

a homeodomain transcription factor involved in many aspects of multicellular development

115
Q

True or False

90% of 46, XX DSD is caused by SRY translocation onto X

A

True or False

116
Q

Define

SRY

A

the sex-determining region of the Y chromosome, found near the chromosome’s pseudoautosomal boundary. Accumulated evidence indicates that a gene in this region encodes the testis-determining factor (TDF)

117
Q

Definition

genes that confer segment identity in Drosophila. They encode homeodomain proteins which interact with Hox and other homeotic genes to initiate segment-specific gene regulation. Homeodomain proteins are transcription factors that share a DNA-binding domain called the homeodomain

A

Homeotic selector (Hox) genes

118
Q

Which signalling molecule precisely defines where limb buds will form?

A

Fgf10

119
Q

Define

Sonic Hedgehog (SHH)

A

key inductive signal in patterning of the anterior-posterior limb axis, the ventral somites and the ventral neural tube

120
Q

Which genes and signalling molecules are involved in testis development?

A

SRY

SOX9

FGF9

121
Q

Which germ layer controls dorso-ventral patterning in the developing limb?

A

Ectoderm

122
Q

Definition

condition in which a single mutation causes multiple phenotypic effects

A

Pleiotropy

123
Q

Define

Disorders of Sex Development

A

medical conditions involving the development of the reproductive system

124
Q

What is the master sex-determining gene in mammals?

A

SRY

125
Q

Which dot is exposure to the highest concentrations of Fgfs?

A

Yellow (then red, then white)

126
Q

Definition

a situation where the phenotype of an organism is determined not only by the environment it experiences and its genotype, but also by the environment and genotype of its mother

A

Maternal effect

127
Q

What is the Apical Ectodermal Ridge required for?

A

Limb outgrowth and proximal-distal development

128
Q

Definition

a maternal effect gene whose protein concentration gradient patterns the anterior-posterior (A-P) axis during Drosophila embryogenesis

A

Bicoid

129
Q

What are the characteristics of Hox genes expressed towards the 3’ end of the DNA?

A

They are expressed more anterior earlier in development

130
Q

Which cells in male mice express SRY?

A

Sertoli cells

131
Q

An example of a morphogen is:

a. A transcription factor that turns on a gene in a cell
b. A diffusible protein that influences cells via a concentration gradient
c. The morphology of an organ is due to several interacting cells
d. One factor turns on more that one other gene within the same cell

A

b. A diffusible protein that influences cells via a concentration gradient

132
Q

Define

Zeugopod

A

A section of an animal’s limb corresponding to the forearm.

133
Q
A
134
Q

What does this interaction lead to?

A

Limb bud outgrowth

135
Q

Define

Syncytium

A

a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei

136
Q

What does an overexpression of Shh cause?

A

Digit defects (i.e. extra digits)

137
Q

Which chromosome of Drosophila are homeotic selector genes found on?

A

III

138
Q

Definition

the linear relationship between the nucleotide sequence in a gene (or the RNA transcribed from it) and the order of amino acids in the polypeptide chain specified by the gene

A

Colinearity

139
Q

What do the Mullerian ducts become in females?

A

Uterus and fallopian tubes

140
Q

Define

Pair-rule genes

A

genes expressed as stripes around the blastoderm embryo during development of the Drosophila embryo

141
Q

Definition

the sex-determining region of the Y chromosome, found near the chromosome’s pseudoautosomal boundary. Accumulated evidence indicates that a gene in this region encodes the testis-determining factor (TDF)

A

SRY

142
Q

True or False:

Cytokinesis between nuclei is occurring during the action of segment polarity genes

A

True

143
Q

Definition

key inductive signal in patterning of the anterior-posterior limb axis, the ventral somites and the ventral neural tube

A

Sonic Hedgehog (SHH)

144
Q

What is the phenotype of XX humans with loss-of-function mutations in R-spo1?

A

Males with testes

145
Q

Define

Fgf10

A

a paracrine signaling molecule seen first in the limb bud and organogenesis development. FGF10 starts the developing of limbs and its involved in the branching of morphogenesis in multiple organs such as the lungs, skin, ear and salivary glands

146
Q

What are the two ducts that are initially present in both sexes?

A

Wolffian and Mullarian ducts

147
Q

Definition

a group of growth factors also known as cytokines considered to constitute a group of pivotal morphogenetic signals, orchestrating tissue architecture throughout the body.

A

Bone Morphogenetic Protein (BMP)

148
Q

Define

Caudal (gene)

A

a maternal effect genes that are important in the formation of more posterior abdominal segments of the Drosophila embryo

149
Q

Define

Pattern formation

A

the developmental process by which cells acquire different identities, depending on their relative spatial positions within the embryo

150
Q

46, XY DSD can explained by ________-of-function of R-spo1/Wnt4 or ________-of-function of SRY/SRY-regulators/SOX9

A

Gain; loss

151
Q

Define

Congenital Adrenal Hyperplasia

A

a form of adrenal insufficiency in which the enzyme that produces two important adrenal steroid hormones, cortisol and aldosterone, is deficient. Because cortisol production is impeded, the adrenal gland instead overproduces androgens (male steroid hormones)

152
Q

Define

Zone of polarising activity (ZPA)

A

an area of mesenchyme that contains signals which instruct the developing limb bud to form along the anterior/posterior axis

153
Q

Definition

a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei

A

Syncytium

154
Q

What phenotypic feature does Drosophila Segment-polarity gene mutants have?

A

Mutants show defects in every segment

155
Q

How does the AER sustain outgrowth of the limb bud?

A

The release of Fgfs that keep cells proliferating underneath the AER

156
Q

How does Wnt4 prevent β-catenin degradation?

A

Wnt molecule binds to the Frizzled receptor causing the recruitment of the LRP receptor which prevents the destruction complex from degrading β-catenin allowing it to enter the nucleus and influence gene expression

157
Q

What signalling molecule is induced by R-SPO1?

A

Wnt4

158
Q

Define

Maternal effect

A

a situation where the phenotype of an organism is determined not only by the environment it experiences and its genotype, but also by the environment and genotype of its mother

159
Q

True or False:

R-SPO1 is expressed in both male and female embryonic gonads

A

False

It is expressed in female but not male gonads

160
Q

Definition

a secreted protein that interacts with WNT4 in the process of female sex development in humans

A

R-spondin1 (R-SPO1)

161
Q

What phenotypic feature does Drosophila pair-rule gene mutants have?

A

Mutants lack portions of every other segment

162
Q

What is the name of the receptor that Wnt binds to?

A

Frizzled

163
Q

Steroidogenic cells in a male embryo become what?

A

Leydig cells

164
Q

What would this lead to?

A
165
Q

Define

Apical Ectodermal Ridge (AER)

A

a structure that forms from the ectodermal cells at the distal end of each limb bud and acts as a major signaling center to ensure proper development of a limb

166
Q

True or False:

The Zone of Polarising Activity (ZPA) is an anterior signalling centre

A

False

It is a posterior signalling centre

167
Q

Definition

a transcription factor that plays a pivotal role in male sexual development by producing a hormone in the Sertoli cells to inhibit the creation of a female reproductive system

A

Sox9

168
Q
A
169
Q

What does the progress zone model of limb outgrowth propose?

A

Proximal-distal patterning is controlled by the amount of time a cell is exposed to Fgfs. The longer they are exposed, the more distal their fate

170
Q

Define

Fibroblast growth factor (Fgf)

A

a family of cell signalling proteins that are involved in a wide variety of processes, most notably as crucial elements for normal development

171
Q

How many Hox clusters do humans have?

A

4

172
Q

Definition

establishment of a specific pattern of gene activity and developmental fate for a given cell, usually prior to any manifestation of the cell’s future phenotype

A

Determination

173
Q

True or False:

90% of 46, XY DSD is caused by SRY mutation

A

False

66% have unknown cause

174
Q

What are the features of 46, XY DSD abnormal testosterone action?

A
  • Gonads normal but defect in testosterone action leads to feminization (e.g. partial or complete Androgen Insensitivity Syndrome (AIS or PAIS)
175
Q

What are each of the stripes expressed by pair-rules defined by?

A

Different types of upstream regulators/enhancers control different stripes

176
Q

What is the phenotype of Lim1 null mice?

A

Paws with two ventral surfaces

177
Q

Which part of the DNA do homeodomains bind to?

A

Major groove

178
Q

Define

Wnt

A

a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors

179
Q

What is the most common cause of 46, XX DSD?

A

Congenital adrenal hyperplasia

180
Q

Definition

a form of adrenal insufficiency in which the enzyme that produces two important adrenal steroid hormones, cortisol and aldosterone, is deficient. Because cortisol production is impeded, the adrenal gland instead overproduces androgens (male steroid hormones)

A

Congenital Adrenal Hyperplasia

181
Q

Definition

a homeodomain transcription factor involved in many aspects of multicellular development

A

Engrailed

182
Q

What phenotypic feature does Drosophila gap gene mutants have?

A

Missing (“gaps”) in body segments

183
Q

A loss-of-function mutation in 21-hydroxylase causes what?

A

Congenital adrenal hyperplasia - build up of testosterone

184
Q

Which model of limb development does this image display?

A

Progress zone model

185
Q

Definition

a paracrine signaling molecule seen first in the limb bud and organogenesis development. FGF10 starts the developing of limbs and its involved in the branching of morphogenesis in multiple organs such as the lungs, skin, ear and salivary glands

A

Fgf10

186
Q

Define

R-spondin1 (R-SPO1)

A

a secreted protein that interacts with WNT4 in the process of female sex development in humans

187
Q

True or False:

Loss of R-spo1 does not affect which sex pathway takes over

A

False

Loss of R-spo1 means male pathway is dominant

188
Q

Bicoid protein ________ translation of caudal mRNA and _________ hunchback

A

Represses; activates

189
Q

What are the two broad categories of Disorders of Sex Development?

A
  1. Gonads can be “normal” but external genitalia atypical
  2. Both gonad and external genitalia can be atypical
190
Q

Is caudal a maternal effect or a gap gene?

A

Maternal effect

191
Q

Which morphogen is responsible for anterior-posterior limb development?

A

Sonic hedgehog (Shh)

192
Q

Define

Homeotic transformations

A

a mutation that causes a tissue normally determined to form a specific organ or body part to alter its pathway of differentiation and form another structure

193
Q

Which model of limb development does this image depict?

A
194
Q

Which maternal mRNA sets up the posterior end of the Drosophila embryo?

A

Nanos

195
Q

Define

Nanos

A

a protein that creates a posterior-to-anterior slope and is a morphogen that helps in abdomen formation

196
Q

As cells in the developing limb leave the progress zone what kind of fate do they have?

A

Proximal fate due to decreasing levels of Fgf exposure

197
Q

How many units does segment polarity genes divide the embryo into?

A

14 units

198
Q

True or False:

Homeotic genes are responsible for directly building characteristic structures

A

False

They provide positional information which tells the cell what it should do

199
Q

What is the sex genotype and phenotype of individuals with AIS?

A

Chromosomally male (XY) but outwardly female body

200
Q

Define

Bicoid

A

a maternal effect gene whose protein concentration gradient patterns the anterior-posterior (A-P) axis during Drosophila embryogenesis

201
Q

Definition

an area of mesenchyme that contains signals which instruct the developing limb bud to form along the anterior/posterior axis

A

Zone of polarising activity (ZPA)

202
Q

Definition

a gene involved in the early stages of pattern formation that define repeated units (metameres) in a segmented organism, usually the embryo

A

Segmentation genes

203
Q

True or False:

Prior to further segmentation by pair-rule genes, the embryo is still a syncytium

A

True

204
Q

Definition

the biological process that causes an organism to develop its shape

A

Morphogenesis

205
Q

True or False:

Determination is irreversible fate commitment

A

True

BMS2042 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions