experimental approaches and model organisms

Question 1

painting

approaches

Answer 1

methods to visualise what cells and tissue give rise to and where genes are expressed

a descriptive approach

the use of labelled cells for the purpose of tracking cell movements and fates during further development

molecular equivalent - taging of mis-expressed molecules with markers
i.e. proteins can be labelled w a epitope tag that can be detected with an antibody or by including GFP
in the vector

Expression: “The molecule in question must be there.”

Question 2

cutting

intervention

Answer 2

methods that query whether a tissue or a gene is necessary to control a process

removal of tissue or the function of a gene and then analyse whether the process now fails

ablation - the removal and discarding of tissue to test whether they are required for a particular developmental even or the isolation of tissues for further testing = donor cells

molecular equivalent = knocking out or knocking down

Inhibition: “If the molecule is inhibited in vitro then the process for which it is thought responsible should fail
to occur.”

3 possible options:
1. make changes to the dna becaus gene experssion is controlled by promoters can be changes to something that is active in more cells and more time points and out of place

2. bring in mRNA directly or using a construct that delivers mRAN to have an RNNa ready to be translated
   - frog and zebrafish use RNA
   - chicken/mouse bring in a plasmid engineered to make mRNA that then can be translated

3, if working with a soluble protein (NOT TRANSCRIPTION FCTORS) signalling molecules
if we want gain of function i.e. signalling protein
can be injected or loaded onto carrier proteins

Question 3

pasting

intervention

Answer 3

methods that ask whether a tissue or a gene is sufficient to control a process you transplant a tissue

transplanting tissues or cells from donor to host embryos can be done between embryos at the same stage of development (isochronic transplants) or at different stages of developments (heterochronic transplants)
can be transplants from donors of a identical size in the host homotopic transplant or and extopic side heterotopic transplants

molecular equivalent = ectopic expression of a molecules with markers

Activity: “The molecule in question must have the appropriate biological activity in a suitable test system.”