Model System Drosophila

Question 1

Introduction of Drosophila als Modellorganismus

Answer 1

1909
Experimente zur Rolle der Chromosomen
Gen Mapping

Thomas Hunt Morgan

Nobelpreis für Physiologie oder Medizin 1933

Question 2

The god fathers of Drosophila Research

Answer 2

T. H. Morgan Noble Price 1933
C. B. Bridges
A. H. Sturtevant

Question 3

Drosophila life cycle

Answer 3

short generation time
9 days @ 25oC

20 days @ 18oC

Question 4

Unterscheidung Geschlecht

Answer 4

Männchen: Punkt am Bein

Question 5

Kultur Drosophila

Answer 5

Agar mit Hefe (Nahrung)
Easy and cheap Culturing
Life Circle Statistik (Folie 12)

Question 6

How to induce mutations?

Answer 6

D. melanogaster white-mutant (1910)

experimenting with: - temperature
- humidity
- light
- injecting salt, acid, toxins etc. in flies did not work

1927 Hermann J. Muller:
- Use of X-ray
adult Drosophila males tolerate 4.000 Rad

Hermann J. Muller
Nobel Prize in Physiology or Medicine 1946

Question 7

1st Golden age of Drosophila

Answer 7

TH Morgan 1910 - X-linked inheritance
AH Sturtevant 1913 - genetic mapping
CB Bridges 1913 - non-disjunction
HJ Muller 1927 - Mutagenesis
deletion, duplication extra X, balancer etc.

Question 8

What are Transposable Elements ?

Answer 8

(mobile DNAs, jumping genes, selfish genes, parasitic DNAs, etc.)
- mobile genetic elements
- size between 100 to 10.000 bp
- jumping from one genomic position
into another
- replicating faster than the host
- insertion mutagenesis
- chromosome instability
- driving force of genome dynamics

Question 9

Activity of TEs in Eukaryotes

Answer 9

organism
Human Mouse Drosophila
TE content
50% 40% 25%
mutation rate
0.2 - 0.4% 10% 80%

Question 10

Applying Transposon for Mutagenesis and Functional Genetics in Drosophila

Answer 10

1. Insertionmutagenesis-lossoffunction
2. Mutationrescue
3. EctopicOver-expression-gainoffunction
4. LacZenhancertrap-Geneexpressioninsitu
5. RNAi-mediatedknock-down

Question 11

1. GeneDisruptionviaTEInsertionMutagenesis

Answer 11

• loss of function mutation,
• often insertions in regulatory sections,
• hypomorphic mutations

Drosophila Vector Tools = DNA Transposons
Folie 22

Question 12

2. Mutation rescue screen

Answer 12

Folie 23

Question 13

3. Ectopic over-expression - gain of function

Answer 13

Folie 24

Question 14

4. P-LacZ enhancer trap
   - Gene expression in situ

Answer 14

Folie 25

Question 15

5. RNAi-mediated gene knock-down

Answer 15

Folie 26
RNA Interference - RNAi
- siRNA
- discovered by A. Fire & G. Mello 1998
- Nobel prize 2006