case unit 4 - disease models Flashcards
why are models of human disease created
to mimic aspects of human disease
to develop and tailor individual therapies and find out fundamental information
why are mice good models
mammals
small
fast-breeding
how can you make mice diabetic
chemical destruction of insulin-producing B-cells to produce hyperglycaemia
why are knock-out mice used
to determine physiological function of a gene
why are knock-in mice used
to introduce specific mutations
describe the process of creatig a mouse model
- design modified embryonic stem cells
- inject into fertilised oocytes in blastocyst stage
- transfer into pseudopregnant females
- breed chimeric offsrping with wild-type mice
- screen for germline transmission
benefits of CRISPR editing
quick
cheap
could be a cure for hereditary diseases
easy to make knock-in/out mice models
why does CRIPSR have a good success rate for knock in/out mice models
you inject specific RNAs into one-celled oocytes then you transfer to pseudopregnant females
what are the limitations of disease models
anatomical and genetic differences to humans
have to extrapolate the results
variations induced by techniques
models often dont live long enough to see disease progression
what is CRISPR-Cas9
genome editing technology
steps involved in CRISPR
- identify unique 20bp region
- clone 20bp sequence
- guide sequence added that hybridises complementarily to target sequence
- Cas9 recruited which binds and cleaves target sequence
what is trio-analysis used for
to see if there is a specific genetic mutation causing the rare disease
what happens in trio-analysis
parents genomes are deep sequenced to see if there is a specific mutation causing the disease in the child
what is a screen used to identify
whether a gene is involved in a process
steps inolved in a screen
identify model organism identify process of interest random mutagenesis (break/mutate individual genes) check if the process still works
