Lecture 6 Introduction to drosophila

Question 1

What did Bridges show in 1914/1916

Answer 1

That chromosomes must contain genes

Question 2

Until 1927 what were scientists interested in?

Answer 2

They were all interested in hereditary which is the genetic transmission of characteristics from parent to offspring.

Question 3

What was shown in 1980s/90s

Answer 3

A range of techniques that use transgenic animals to either visualise, misexpress or reduce gene expression

Question 4

What did enhancer traps show

Answer 4

promotor trapping

Question 5

What did Gal/UAS show

Answer 5

gene misexpression

Question 6

What did FLP/FRT show

Answer 6

‘clonal’ mutant analysis

Question 7

What did RNAi show

Answer 7

ex vivo and in vivo

Question 8

What did ‘omic’ technologies show

Answer 8

genome, transcriptome, proteome etc.

Question 9

How long is the Drosophila genome

Answer 9

143, 726, 002 bp in length

Question 10

What did aligning the genome of different drosophila show

Answer 10

shows protein coding exons/ regulatory proteins e.g. enhancers/TF are well conserved in different species because they are encoding proteins. They are of high significance and there are only a limited number of ways to code for a certain protein if you want it to continue to function.
Introns are not conserved as they do not encode proteins.

Question 11

How do females and males mate i.e. monogamy etc

Answer 11

• Females ‘play the field’ to find the most suitable partner to mate with
• Males want monogamy so that the female produces your offspring
• Therefore, males have sex peptides that adhere to the tail of the sperm, makes the female non-receptive to the courtship behaviour of other males
• Females have anti-peptides to stop this interaction
• This is why you end up with long sperm tails e.g. Drosophila bifurca (50mm)

Question 12

How many eggs are made at once

Answer 12

Many

Question 13

How many times do females need to mate

Answer 13

Once

Question 14

Define stem cell maintenance in females

Answer 14

Stem cells are right at the tip with surrounding cells that remain as stem cells and cells further away differentiating into eggs

Question 15

Describe puffs in polytene chromosomes

Answer 15

• Puffs an extremely active gene
- Polymerase II (green stain) makes RNA for protein coding genes shows this is usually in areas of the genome which are puffed up/biggest as gene transcription is happening here

Question 16

How many bands are in polytene chromosomes and what is there kB

Answer 16

• Approx. 5000 bands, each approx. 22 kb

Question 17

What do nurse cells produce

Answer 17

Maternal factors for the developing oocyte
• Proteins and RNAs made in nurse cells
• Transferred into developing oocyte
• Allow progeny to develop quickly

Question 18

What stages are there in egg development

Answer 18

• There is no G phase/cell division (only S and M) to allow rapid division of the nuclei.

Question 19

Describe segments of a drosophila

Answer 19

T1-T3, A1-A8

Question 20

At 2 hours what is the drosophila called

Answer 20

Syncytial blastoderm

Question 21

3 hours what is drosophila called

Answer 21

Cellular blastoderm

Question 22

Name common IC signals used in drosophila

Answer 22

HH - Ptc (receptor) for patterning of insect segments and positional signalling in insect leg and wing discs

Wng - Frizzed R - for segment/imaginal disc segmentation

Delta/serrate - Notch R - for oocyte polarity

TGF alpha - EGF R - polarisation of oocyte

Dpp (TGFbeta) - for DV patterning and patterning of imaginal discs

FGF - FGF R - migration of tracheal cells