Biochemistry - Drosophilia Genetic Control

Question 1

How can gene-differentiation interactions be identified?

Answer 1

Studying abnormalities

Question 2

Early stages of development in drosophilia…

Answer 2

The Earliest stages of development are done-so in the oocyte, where mutations can affect development plan, being maternal-effect genes

Question 3

Maternal Genes

Answer 3

Genes whose product are produced or deposited into the oocyte.

Question 4

Where are zygotic genes important?

Answer 4

Embryo functioning developmental genes

Question 5

What do zygotic genes do?

Answer 5

These interpret/respond to the positional information laid out in the egg by the maternal-effect gees

Question 6

Pattern in drosophilia.

Answer 6

Segementation of 14 denticles, marking the basic insect body plan of 3 thoraic segments, 8 abdominal segments and three head segments

Question 7

Parasegments

Answer 7

Consist of posterior region of one segment and the anterior region of another.

Question 8

Four types of segmentation genes…

Answer 8

Co-ordinate Genes
Gap genes
Pair-rule genes
Segment-polarity genes

Question 9

Co-Ordinate Genes

Answer 9

Determine co-ordinate axis of the embryo, that is the anterior-posterior axis and the dorsal-ventral axis.

Question 10

How do the co-ordinate genes define the axis?

Answer 10

Polarity and gradients

Question 11

What is anterior/head and thorax formation regulated by?

Answer 11

Bicoid gene

Question 12

Bicoid Genes

Answer 12

Morphogens control embryonic gene expression by transcriptional activation and translational repression.

Question 13

What is the product of the bicoid gene?

Answer 13

A TF for anterior-structure genes, produced by nurse cells, exported to anterior region of the oocyte

Question 14

Mechanisms of bicoid…

Answer 14

Helix-turn-helix domain invades the DNA grooves, the genes activated containing upstream regions.

Question 15

How can bicoid be regulatied?

Answer 15

Differences in two nucleotides can regulate bicoid affinity

Question 16

What do the posterior genes affect?

Answer 16

The abdomen

Question 17

What do terminal genes affect?

Answer 17

The most posterior and most anterior like the torso gene.

Question 18

Gap Genes

Answer 18

Code for variour TF that form short-ragne morphogenic gradients, establishing next level of spatial organization.

Question 19

What are gap genes function?

Answer 19

Defined by because mutations result in absence of pattern elements derived from contigous segments

Question 20

Example of a gap gene…

Answer 20

Hunchback gene

Question 21

How is hunchback expression is controlled?

Answer 21

When the effects of bicoid and nanos genes are offset

Question 22

Function of Nanos…

Answer 22

Repress activation of bicoid, establishing an anterior-posterior gradient.

Question 23

Pair-Rule Genes

Answer 23

Seperate the embryo into segments

Question 24

Function of pair-rule genes…

Answer 24

Distinguish segmentation in the larvae, wiwth repetetiveness and indivdiually of the segments…

Question 25

Example of pair-rule gene...

Answer 25

Hairy gene

Question 26

Hairy gene

Answer 26

The earliest expressed, positvely/negatively regulated by hunchback/lruppel and other gap genes

Question 27

Segment-Polarity Genes

Answer 27

Determine anterior-posterior axis development pattern

Question 28

Function of the segment-polarity gene

Answer 28

They create spatial differentiation within each segment...

Question 29

Example of segment-polarity genes...

Answer 29

The engrailed gene, dividing segments into anterior/posterior divisions.

Question 30

What do imaginal disks in metamorphis form?

Answer 30

Tissues and structures

Question 31

Example of imaginal disk structures?

Answer 31

Haltere wing disks

Question 32

What does ecydosone in pupal stage regulate?

Answer 32

Break down of larval tissues/organs

Question 33

Homeotic Genes

Answer 33

Give rise to identity of the segments, not producing any segments

Question 34

Mutations in homeotic gene...

Answer 34

Cause tranformation into irrelevant structures...

Question 35

Example of homeotic mutation?

Answer 35

Bithorax where the third thoracic segment into the anterior fo the second thoracic segments results in haltere forming an ADDITIONAL pair of wings.

Question 36

Function of HOX genes?

Answer 36

Control differentiation in many organisms of the nervous system, musculature and skeleotns.

Question 37

Example of the HOX gene conservation...

Answer 37

PAX6 gene which has identifcal amino acid sequneces in humans and mice AND drosophilia.

Question 38

What is PAX6 foudn in?

Answer 38

Planarians, octopus, vertebrates and insect compound eyes.