Transcript Screening for clinically important genes

Screening for clinically
important genes
E – Describe an example of the use of genetic
screening
D – Explain in detail how different methods work
C – Evaluate the ethics of gene technologies
DNA Probe
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Single strand of DNA
Known sequence
Restriction endonucleases
Label probe radioactively
Hybridization
Cystic fibrosis or mutated gene
Restriction Mapping
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http://www.channel4.com/learning/microsites/
G/genetics/activities/chrom11.html an activity
where you get to be a genetic counsellor
Genetically Inherited diseases
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Just a quick recap –
Diseases can be either dominant or
recessive – how does this affect the
genotype that the individual must have
to display the disease?
Genetic Screening
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If individuals have a family history of an
inherited disease they may choose to be
screened for the disease.
This will enable them to find out if the
have a mutated gene, and the
probabilities of the offspring inheriting
the gene.
Screening for Sickle cell
anaemia
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Using figure 1 on page 272 – draw your
own cartoon script to explain to
someone with the possibility of sickle
cells anaemia how the test works
What to do with the results
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Genetic counselling – once the tests results
are back people have to be given the
information so that they can make informed
decisions on the basis of the result.
This is the same for other mutated genes –
e.g. the inheritance of mutated oncogenes –
tumour suppressor genes – if people carry
mutated genes and have an increased likelihood
of developing cancer they may decided to
make lifestyle changes, it may inform other
medical treatment that they have, it may
encourage them to talk to the offspring about
being tested etc….
Activity
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Read the article about sickle cell
anaemia and highlight the important
points.
Complete the application question which
starts on page 273.
Implications of genetic
screening
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Now that we have the technology, we have to
take responsibility for how it is used, some
key issues:
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Who is tested?
Who has access to the results?
Who takes responsibility for someone who carries
a gene of an inherited disease – is it better to
abort or have a life of suffering?
Should we select against mutated genes or do we
need to maintain diversity?
Who decided what is a defect and what is a
disease – is ADHD and aspergers a defect or
disease?
Some difficult questions
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Question: If you know from testing that you are at risk from a
serious disease, do you have an equal right to life insurance as
someone who does not carry this genetic condition?
Question: You run a small company that relies on all its staff
working full time to survive. You have to make a key appointment to
the managerial staff. The best candidate suffers from a genetic
condition that will require her to have regular hospital treatment,
needing time off. The second best candidate does not have this
condition, and your colleagues think he would be a safe bet. Does
this affect who you appoint?
Question: A mum has had 6 boys and then gave birth to a much
loved little girl however she was killed in a road traffic accident, they
want to use embryo screening and IVF so that they can have another
little girl, you are on the board who decided what do you think
should happen?