Genetic Screening

Card Set Information

Genetic Screening
2014-04-14 20:13:04
Biology Genes camturnbull

AQA BIOL5 Genetic screening
Show Answers:

  1. What can genetic screening be used for?
    To find out if someone has a copy of a mutated gene
  2. 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
  3. Describe stage 1 of genetic screening
    A radioactive probe is made containing radioactive nucleotides in the same sequence as the mutated region
  4. Describe stage 2 of genetic screening
    PCR is used to make millions of copies
  5. Describe stage 3 of genetic screening
    DNA from the individual's cell is taken and treated to make it single stranded
  6. 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
  7. Describe stage 5 of genetic screening
    Autoradiography is used to detect whether hybridisation has occurred
  8. 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
  9. What is the percentage chance of the children of two carriers inheriting their disease?
  10. 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
  11. 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