Genetics of development

Question 1

What are homeotic mutants?

Answer 1

one part of the body is transformed to another part

Question 2

Why are drosophilia a good model?

Answer 2

Has striking mutants- looks way different in mutants, also low cost, east to breed, and has a fast life cycle

Question 3

What is bithorax?

Answer 3

two sets of wings

Question 4

What is antennapedia?

Answer 4

is legs instead of antennas

Question 5

What is the bithorax and antennepedia mutations derived from?

Answer 5

one mutated gene

Question 6

Within the thorax how many regions are there?

Answer 6

3

Question 7

Within abdomen how many sections are there?

Answer 7

8

Question 8

What is the anteriorposterior axis?

Answer 8

Is the head to bottom axis, is head versus rear

Question 9

What is morphogen?

Answer 9

Molecule whose effects are concentration dependent, and establish the pattern of tissue development and body plan formation

Question 10

How is gene expression diff in space and time?

Answer 10

some genes are turned on in only head, some are only turned on in adult stage versus juvenile stage

Question 11

What do morphogen gradients determine?

Answer 11

Hox gene expression

Question 12

What do hox genes do?

Answer 12

Control the identity of segments and appendages, also encode transcription factors

Question 13

What is the genetic toolkit?

Answer 13

Is hox genes and genes that regulate them
are set of genes responsible for regulating animal developments, mostly encode cell signaling and transcription factors

Question 14

What does it mean that hox genes are conserved across diverse species of animals?

Answer 14

they stay the same in their toolkit across alot of animals

Question 15

Wat are the five classes of toolkit genes involved in regulating ap BODY AXIS?

Answer 15

Maternal effect genes
Gap genes
Pair rule genes
Segment-polarity genes
Hox genes

Question 16

What are maternal effect genes?

Answer 16

They are the first class of toolkit genes that established the anterior and posterior end of the animal
Are expressed in the mother
Mutant phenotypes of maternal effect genes depend only on the genotype of mom

Question 17

What two genes are maternal expressed genes? Where are they tethered?

Answer 17

Bicoid (anterior) and Nanos mRNA (posterior)

Question 18

Upon fertilization what happens to the bicoid and nanos proteins?

Answer 18

They get expressed and form a gradient

Question 19

What do Bicoid and nanos encode?

Answer 19

They encode transcription factors that regulate expression of the next set of genes

Question 20

Say a female was homozygous recessive what happens to the egg, is it WT or mutant?

Answer 20

mutant

Question 21

Say the female had genotype that was heterozygous, and the male was homozygous, are any offspring mutant?

Answer 21

NO! since mom is WT all offspring WT. Is a maternal effect gene

Question 22

What genes are zygotically expressed?

Answer 22

Gap genes, pair rule genes, segment polarity genes, hox genes

Question 23

Maternal effect genes have what role in the toolkit?

Answer 23

establishing interior and posterior (bicoid and nanos)

Question 24

What are segmentation genes? What do they do?

Answer 24

Gap genes, pair rule genes, segment polarity genes, effect the number and organization of drosophila body segments

Question 25

What do gap genes divide the embryo into?

Answer 25

broad regions

Question 26

What does a mutated version of Kruppel do? What does this tell us?

Answer 26

It eliminates body segments in the anterior, is not viable, so gap genes lead to proper segmentation

Question 27

What do pair rule genes affect?

Answer 27

Affect the development of pairs of segments

Question 28

If you mutate pair rule gene hairy what happens?

Answer 28

The embryo misses every other segment, pair rule genes act in more narrow regions than gap genes

Question 29

What segment polarity genes affect?

Answer 29

The organization of segments, mutations in this causes the mis organization within a particular segment.

Question 30

What do gap genes do?

Answer 30

Define regional sections

Question 31

What pair rule genes do?

Answer 31

Define individual segments

Question 32

What do segment polarity genes do?

Answer 32

define organization of individual segments

Question 33

The order of hox genes in the chromosome responds to what?

Answer 33

The the order of body regions that are affected by each Hox gene.

Question 34

Where are hox genes expressed? What do they give rise to?

Answer 34

Expressed in restricted regions in the embryo, give rise to the corresponding adult body part

Question 35

How do HOX genes control the identity of segments and appendages?

Answer 35

They are transcription factors so they regulate expression of networks of other genes

Question 36

Are hox genes sequence specific DNA binding proteins?

Answer 36

Yes

Question 37

What do HOX genes bind to in the sequence?

Answer 37

cis acting regulatory sequences of other genes to activate and repress them

Question 38

Are all genes in the toolkit transcription factors?

Answer 38

yes

Question 39

What is hunchback?

Answer 39

is a promoter which bicoid binds to to to express the gap gene

Question 40

IS the hunchback expression and bicoid protein both have gradients?

Answer 40

yes

Question 41

How many sites does bicoid bind to to activate expression of hunchback?

Answer 41

has to be three sites

Question 42

What concentration of bicoid do we need to have hunchback work?

Answer 42

high levels, need a threshold level to do it

Question 43

What is eve?

Answer 43

A pair rule gene, cis acting regulatory elements control expression of it by binding to transcription factors