DNA probes, Hybridisation and Genetic Sequencing Flashcards
Give 2 ways that genes can be located.
Using DNA probes and DNA hybridisation.
What is a DNA probe?
A short single stranded section of DNA that has a label attached to it.
Give 2 different things that can be labels that can attach to DNA.
Radioactive isotopes
Fluorescent labelled probes
How are radioactive isotope probes identified?
Using a photographic plate
How are fluorescently labelled probes identified?
Identified when they emit light
What are DNA probes complimentary to?
The target gene.
What do gene probes do when they find the target gene?
They hybridise and the fluorescent marker or radioactive isotope attaches.
What does digestion of DNA mean?
DNA is cut up.
What enzyme digests DNA?
Restriction endonucleases.
Name an analytical process that can separate DNA after digestion has occurred.
Gel electrophoresis
Define hybridisation.
DNA probe binds to complimentary bases.
What is genetic counselling?
Where parents are screened for genetic disease and advice is given to parents to help them make an informed choice whether to have a child.
Describe how the DNA probe is formed during genetic screening.
Mutated gene identified and fragment of DNA complimentary to this is produced
The fragment is radioactively labelled to form a DNA probe
During DNA sequencing, how are mutated genes identified using DNA probes?
Probes are added to DNA fragments from the person being screened.
If the donor has the mutated gene then the probe will bind to complementary bases on the donor DNA.
Why is it important to screen people who have family history of a disease?
They may be carriers of a mutant allele
