BGM1004/L21 Model Organisms Flashcards
What is developmental biology?
The study of the process by which organisms grow and develop
What does developmental genetics focus on? (3)
Growth, differentiation and morphogenesis
Why is developmental biology important? (2)
Understanding congenital malformations
Understanding regeneration, repair, ageing and cancer
In mammals, what is the development period considered to be?
Between fertilisation and birth
What is a developing organism in humans called?
Embryo (or fetus once fully formed)
How long is human pregnancy?
38-40 weeks
How long is the embryonic period of gestation in humans?
8 weeks
When does most organogenesis occur in humans?
Embryogenesis (first 8 weeks)
When do most congenital anomalies occur in humans?
Embryogenesis (first 8 weeks)
What are the 3 general approaches to studying development?
Anatomical
Physical
Genetic
What is considered in the anatomical approach of studying development?
How things look as they form
What is considered in the physical manipulation approach of studying development?
What happens if developing structures are interfered with
What is considered in the genetic approach of studying development?
How genes control development
What is a model organism?
A well-established experimental biological system
Name 4 model organisms for studying development.
Mouse
Chicken
Frog
Zebrafish
Fruit fly
Bird
What gene in mice can trigger eye development in Drosophila?
Pax6 gene
What gene controls cardiac development in humans?
Nkx2.5
What is the oldest known bilaterian at 550 million years?
Ikaria wariootia
What are homeobox genes?
Genes determining physical structure of the body
What is tempero-spatial colinearity?
The order of segments on the body reflecting in their order on their chromosome
Why is Drosophila a good model organism? (4)
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
Why are zebrafish a good model organism? (4)
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
Why are Newts and Xenopus (clawed toad) good for physical manipulation?
Large embryos allow easy manipulation
Why are amphibians useful as model organisms? (3)
Large embryos easily manipulated
More similar anatomically to mammals than flies or fish
Capable of regenerating many body parts
Why are birds useful as model organisms? (3)
Large accessible eggs
Easy to manipulate and image
Anatomically (organ level) very similar to humans
Give a disadvantage to using birds as a model organism.
Large complex genomes
Why are mice useful as a model organism? (3)
Genome sequenced
Very similar to human
Large number of mutants available
Possible to manipulate genome
Relatively rapid life cycle
Give 3 examples of genetic tools.
Morpholinos
Chemical mutagenesis (ENU)
Transgenesis (transient/germline)
Single gene knockouts and knockins
Conditional gene knockouts
CRISPR
What is a morpholino?
A synthetic antisense oligonucleotide designed to bind and block translation initiation complex of mRNA
What is chemical mutagenesis (ENU)?
Interaction between cells in different physical stress and chemical compounds that alter DNA structure
What is transgenesis (transient)?
Temporarily introducing foreign DNA into a plant cell
What is transgenesis (germline)?
Insertion of a gene into a genome, followed by germline transmission of the gene and analysis of phenotype
What is a single gene knockout/knockin?
(In)activation or removal of one or more specific genes from an organism
What is a conditional gene knockout?
Technique eliminating expression of a specific gene at a specific time in a given tissue
What is CRISPR?
Technique used to selectively modify DNA of living organisms
Why are animal models required?
Can’t experiment on humans
Model disease processes
Test toxicity of new drugs
Model complex development
*Exceptions to all exist
Why can’t humans be used for experiments? (2)
Ethical reasons
Human genetics very complex
What are human organoids?
Self-organising three-dimensional cell cultures
What are human organoids derived from?
Pluripotent stem cells
What makes a good model for developmental genetics research? (5)
Genome sequenced
Anatomically resembles human at some level
Rapid rate of development
Large numbers of offspring per generation
Easily manipulated
Genetically tractable
Readily available
