BGM1004/L21 Model Organisms

Question 1

What is developmental biology?

Answer 1

The study of the process by which organisms grow and develop

Question 2

What does developmental genetics focus on? (3)

Answer 2

Growth, differentiation and morphogenesis

Question 3

Why is developmental biology important? (2)

Answer 3

Understanding congenital malformations
Understanding regeneration, repair, ageing and cancer

Question 4

In mammals, what is the development period considered to be?

Answer 4

Between fertilisation and birth

Question 5

What is a developing organism in humans called?

Answer 5

Embryo (or fetus once fully formed)

Question 6

How long is human pregnancy?

Answer 6

38-40 weeks

Question 7

How long is the embryonic period of gestation in humans?

Answer 7

8 weeks

Question 8

When does most organogenesis occur in humans?

Answer 8

Embryogenesis (first 8 weeks)

Question 9

When do most congenital anomalies occur in humans?

Answer 9

Embryogenesis (first 8 weeks)

Question 10

What are the 3 general approaches to studying development?

Answer 10

Anatomical
Physical
Genetic

Question 11

What is considered in the anatomical approach of studying development?

Answer 11

How things look as they form

Question 12

What is considered in the physical manipulation approach of studying development?

Answer 12

What happens if developing structures are interfered with

Question 13

What is considered in the genetic approach of studying development?

Answer 13

How genes control development

Question 14

What is a model organism?

Answer 14

A well-established experimental biological system

Question 15

Name 4 model organisms for studying development.

Answer 15

Mouse
Chicken
Frog
Zebrafish
Fruit fly
Bird

Question 16

What gene in mice can trigger eye development in Drosophila?

Answer 16

Pax6 gene

Question 17

What gene controls cardiac development in humans?

Answer 17

Nkx2.5

Question 18

What is the oldest known bilaterian at 550 million years?

Answer 18

Ikaria wariootia

Question 19

What are homeobox genes?

Answer 19

Genes determining physical structure of the body

Question 20

What is tempero-spatial colinearity?

Answer 20

The order of segments on the body reflecting in their order on their chromosome

Question 21

Why is Drosophila a good model organism? (4)

Answer 21

Genome sequenced
Most genes have mammalian homologues
Many mutants available
Short life cycle
Large easily accessed larvae
Allows understanding of basic gene networks regulating early body plan

Question 22

Why are zebrafish a good model organism? (4)

Answer 22

Genome sequenced
Genetically more similar to man than fly
Fundamental developmental processes similar to mammals
Easy to manipulate genetically/experimentally
Capable of regenerating many body parts
Transparent embryos

Question 23

Why are Newts and Xenopus (clawed toad) good for physical manipulation?

Answer 23

Large embryos allow easy manipulation

Question 24

Why are amphibians useful as model organisms? (3)

Answer 24

Large embryos easily manipulated
More similar anatomically to mammals than flies or fish
Capable of regenerating many body parts

Question 25

Why are birds useful as model organisms? (3)

Answer 25

Large accessible eggs Easy to manipulate and image Anatomically (organ level) very similar to humans

Question 26

Give a disadvantage to using birds as a model organism.

Answer 26

Large complex genomes

Question 27

Why are mice useful as a model organism? (3)

Answer 27

Genome sequenced Very similar to human Large number of mutants available Possible to manipulate genome Relatively rapid life cycle

Question 28

Give 3 examples of genetic tools.

Answer 28

Morpholinos Chemical mutagenesis (ENU) Transgenesis (transient/germline) Single gene knockouts and knockins Conditional gene knockouts CRISPR

Question 29

What is a morpholino?

Answer 29

A synthetic antisense oligonucleotide designed to bind and block translation initiation complex of mRNA

Question 30

What is chemical mutagenesis (ENU)?

Answer 30

Interaction between cells in different physical stress and chemical compounds that alter DNA structure

Question 31

What is transgenesis (transient)?

Answer 31

Temporarily introducing foreign DNA into a plant cell

Question 32

What is transgenesis (germline)?

Answer 32

Insertion of a gene into a genome, followed by germline transmission of the gene and analysis of phenotype

Question 33

What is a single gene knockout/knockin?

Answer 33

(In)activation or removal of one or more specific genes from an organism

Question 34

What is a conditional gene knockout?

Answer 34

Technique eliminating expression of a specific gene at a specific time in a given tissue

Question 35

What is CRISPR?

Answer 35

Technique used to selectively modify DNA of living organisms

Question 36

Why are animal models required?

Answer 36

Can't experiment on humans Model disease processes Test toxicity of new drugs Model complex development *Exceptions to all exist

Question 37

Why can't humans be used for experiments? (2)

Answer 37

Ethical reasons Human genetics very complex

Question 38

What are human organoids?

Answer 38

Self-organising three-dimensional cell cultures

Question 39

What are human organoids derived from?

Answer 39

Pluripotent stem cells

Question 40

What makes a good model for developmental genetics research? (5)

Answer 40

Genome sequenced Anatomically resembles human at some level Rapid rate of development Large numbers of offspring per generation Easily manipulated Genetically tractable Readily available