Large scale genetic screens in zebrafish

Question 1

How are model systems representative?

Answer 1

Developmental processes are v fundamental, so there is a lot of similarity in the development of organisms

Question 2

What makes model systems a necessity?

Answer 2

Ethics of studying things in humans, as well as costs

Question 3

Examples of using model organisms?

Answer 3

Observing development and morphological analysis
Manipulating an embryo
Developmental genetics

Question 4

Characteristics of a model organism for observing development and morphological analysis?

Answer 4

large eggs, accessible embryos, short development time, and easy to keep in the lab.

Question 5

Model organisms for observing development and morphological analysis?

Answer 5

Zebrafish, frog, chicken

Question 6

Characteristics of a model organism for embryo manipulation?

Answer 6

large accessible embryos, robust embryos that can tolerate manipulation or embryos that can be grown in a dish, in culture.

Question 7

Model organisms for embryo manipulation?

Answer 7

Frog and chicken

Question 8

Characteristics of a model organism for developmental genetics?

Answer 8

ease of breeding in the laboratory, short generation interval, simple or small genome and ease of observing embryos to see mutant effects.

Question 9

Suitable model organisms for studying developmental genetics?

Answer 9

Nematode worm, fruit fly, zebrafish and mouse

Question 10

Why is the frog not good for studying developmental genetics?

Answer 10

It is tetraploid–> complex genome

Question 11

Why are zebrafish used as a model organism?

Answer 11

Speed, size, transparency, numbers, genetics

Question 12

Zebrafish speed of development?

Answer 12

significant phases of embryogenesis occur within a relatively short time period

Question 13

Size of zebrafish?

Answer 13

embryos large enough to be screened under dissecting microscope

Question 14

Zebrafish transparency?

Answer 14

Complete, even chorion (shell) accessibility for in vivo imaging of cell and tissue behaviours

Question 15

Zebrafish transparency benefit?

Answer 15

Little manipulation needed don’t need fixing or processing for microscopy

Question 16

Zebrafish offspring number?

Answer 16

High, up to 600 per clutch

Question 17

Zebrafish offspring number benefit?

Answer 17

Increase statistical power–> larger sample size

Question 18

Zebrafish genetics?

Answer 18

tractable genetic model–> Genome size isn’t small, but it is diploid and readily manipulated

Question 19

Example of a genetic study that can be done on zebrafish?

Answer 19

Triple homozygote–> 3 gene mutant
need large numbers of embryos to get the statistics to look at 3 gene mutant phenotypes

Question 20

What is a genetic screen?

Answer 20

A laboratory procedure used to create and detect a mutant organism.

Question 21

What do genetic screens look at?

Answer 21

Genes involved in certain processes

Question 22

How are genetic screens done?

Answer 22

Create a mutant organism and see if the mutant has the process affected

Question 23

Types of genetic screens?

Answer 23

Forward genetic, reverse genetic

Question 24

How is a forward genetic screen done?

Answer 24

Make random mutants
See if the process youre interested in is affected in any of them
If it is then look what gene is mutated in that individual

Question 25

What is mutagenesis?

Answer 25

process by which the genetic information of an organism is changed, resulting in a mutation

Question 26

What is a forward genetic screen?

Answer 26

It is the classical genetics approach of identifying a gene by its mutant phenotype. Also known as random mutagenesis screening.

Question 27

Mechanisms of chemical mutaganesis?

Answer 27

Physical, chemical and biological agents High temp, radiation et

Question 28

How are fish usually mutated?

Answer 28

Treatment with N-ethylnotrosourea (ENU)

Question 29

Which parent is usually treated with the mutagen?

Answer 29

Male

Question 30

What is one with the mutated male?

Answer 30

Bread from to make offspring