Model Organisms

Question 1

what genes are so similar across species that they are interchangeable

Answer 1

master regulatory genes

Question 2

why are master regulatory genes similar across species

Answer 2

there has been strong conservation of genes and function over long evolutionary distances

Question 3

describe 3 factors that make drosophila ideal model organisms

Answer 3

1. fully mapped genome (only a few chromosomes in the whole thing)
2. short life cycle
3. complex behaviours and organ structure

cheap & ethical

Question 4

give an example of where drosophila have been used to address a specific neurobiological question

Answer 4

in circadian rhythms - period mutants have been generated and the effect on their period cycle has been investigated. Proven period is critical for maintaining rhythmicity

also used to measure locomotor activity and their response to sleep deprivation

Question 5

how many neurons in C. elegans

Answer 5

302 neurons

Question 6

why are c. elegans good to study

Answer 6

transparent nervous system which is easy to visualise
few neurons which are easy to manipulate

Question 7

give an example of where C. elegans have been used to address a neurobiological question

Answer 7

learning and memory: habituation
- in response to repeated mechanical stimulation in the tap-withdrawal response, the worm becomes habituated - both the amplitude and frequency of the response decreased

Question 8

what neurons mediate the tap-withdrawal response

Answer 8

mechanosensory cells and interneurons

Question 9

name 2 limitations of studying mice

Answer 9

tighter ethical regulations
costly to house

Question 10

what is the benefit of studying mice

Answer 10

closer resemblance of the human genome

Question 11

given an example where the study of mice has helped address a specific neurobiology research question

Answer 11

learning and memory - KO of NMDA receptors in the CA1 subfield impaired memory and LTP.

Question 12

how are model organisms studies (2)

Answer 12

1. behaviourally
2. genetically

Question 13

name 2 paradigms used to study learning and memory behaviour

Answer 13

the 8 arm radial maze task
the Morris water maze

Question 14

how can behaviour be assessed in courtship

Answer 14

evaluation of the 4 courtship behaviour parameters:
1. latency to initiate courtship
2. latency to copulate
3. total time courting
4. order of the courtship steps performed correctly

Question 15

what is an example of forward genetics

Answer 15

random mutagenesis

Question 16

what is forward genetics

Answer 16

observing the effect on phenotype and then identifying the mutant gene responsible

Question 17

what is backward genetics

Answer 17

observing the effect of a specific gene on the phenotype

Question 18

give an example of backward genetics

Answer 18

site directed mutagenesis

Question 19

how can GAL4/UAS system be used to express genes

Answer 19

cross a GAL4 carrying fly in the tissue type of interest with a fly carrying the target gene downstream of the UAS promotor

• offspring will express the gene of interest

Question 20

what is GAL4

Answer 20

a transcription factor taken from yeast

Question 21

what is used to knockout genes

Answer 21

CRISPR gene editing