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What can genetic screening be used for?
To find out if someone has a copy of a mutated gene
What happens if someone possesses one copy of a mutated gene?
They are said to be carriers
They are unaffected by the disease
They could, however pass it on to their children
Describe stage 1 of genetic screening
A radioactive probe is made containing radioactive nucleotides in the same sequence as the mutated region
Describe stage 2 of genetic screening
PCR is used to make millions of copies
Describe stage 3 of genetic screening
DNA from the individual's cell is taken and treated to make it single stranded
Describe stage 4 of genetic screening
The probe is added to the single stranded DNA and if the person possessed the mutated gene the probe will hybridise to the DNA
Describe stage 5 of genetic screening
Autoradiography is used to detect whether hybridisation has occurred
What happens if genetic screening reveals the presence of a gene that could cause disease
Genetic counselling takes place to discuss the best course of action
What is the percentage chance of the children of two carriers inheriting their disease?
How might genetic counselling help two carriers?
Information is provided to enable decisions to be made
For instance whether or not the have children or to undergo IVF and screen the embryos for presence of the allele
How might Genetic counselling help patients with oncogenes?
The presence of some oncogenes can cause cancer
The patient is informed of the risk factors to avoid to reduce the likelihood of tumour growth
Regular screening can take place to diagnose the cancer early or the organ in question can be removed entirely
Biology Genes camturnbull
AQA BIOL5 Genetic screening