Model organisms for studying development (lecture 21) Flashcards
what is developmental biology?
the study of the process by which organisms grow and develop
focuses on growth, differentiation and morphogenesis
important for understanding congenital malformations
what is morphogenesis?
the creation of shape
what is development?
the period between fertilisation and birth
developing organism is known as an embryo
what are the 3 general approaches to studying development?
anatomical
experimental manipulation
genetic
anatomical approach to studying development
what things look like as they develop
the oldest approach
what parts of the embryo form what?
how do the cells position themselves?
how does this relate to this?
anatomical manipulation approach to studying development
what happens if you interfere with developing structures
what happens if you remove a specific region?
how do drugs affect development?
what happens if you transplant it to a new site?
genetic approach to studying development
how genes control development
how do specific genes give instructions for complex form?
how do sets of genes integrate their instructions?
do mutations explain congenital malformations?
what is a model organism?
a well-established experimental biological system
why are drosophila (fruit flys) useful?
genetics
- most genes have homologues in mammals
- many mutants available
- short life cycles
- large easily accessed larvae
- allowed us to understand the basic gene networks that regulate the early body plan
why are zebrafish useful?
genetic and manipulation
- more genetically similar to man than fly
- fundamental developmental processes similar
- easy to genetically manipulate eggs
- capable of regenerating many body parts
- are transparent as embryos
- relatively cheap
why are newts and xenopus useful?
manipulation
- large embryos can be easily manipulated
- more similar anatomically
- capable of regenerating many body parts
not as popular anymore as
• have a longer life cycle
• expensive to keep
why are chickens and quails useful?
manipulation and anatomical
- large accessible eggs
- easy to manipulate and image
- anatomically similar to humans
- complex genetics
why are mice useful?
genetics and anatomy
- anatomically similar to humans
- large number of mutants available
- can manipulate genome
- rapid life cycle
issues
• difficult to physically manipulate as develop in utero
• affordable but expensive to look after
• more ethical issues
why can man not be used as a model organism?
cannot genetically manipulate as ethical issues
human genetics very complex
limited access to human embryos
what genetic tools are available to us?
- morpholinos
- chemical mutagenesis
- transgenesis (transient and germline)
- single gene knockouts and knockins
- condition gene knockouts
- CRISPR
why do we need animal models?
- can’t experiment on humans
- can’t model disease processes in cell culture
- canniest toxicity of new drugs or disease treatments in cell culture
- cant model development or ageing in cell culture
what are human organoids?
self-organised 3D cell cultures
derived from stem cells
recapitulate early stages of development in a dish
have been created for many organs • eye • brain • intestine • kidney • liver
potentials of organoids?
drug testing
test drug safety
transplantation
disease modelling
what makes a good model organism for developmental genetics?
genome sequenced anatomically resembles human rapid rate of development to maturity large numbers of offspring per generation easily manipulated readily available
