8B Gene Probes and Medical Diagnostics Flashcards
What are gene probes
short strands of DNA that have a specific base sequence that is complementary to the base sequence of a part of target allele
What happens if a target gene is present in DNA
the gene probe will hybridise to it
What are gene probes used for
to locate specific alleles of genes or to see if a person’s DNA contains a mutated allele that causes a genetic disorder
What do DNA probes have attached to them
a label attached so it can be detected common types are a radioactive or fluorescent label
How is gene probing done with a tag
A sample of DNA is digested into fragments using restriction enzymes and separated using electrophoresis
The fragments are then transferred to a nylon membrane and incubated with the fluorescently labelled DNA probe
If the allele is present the DNA probe will hybridise to it
The membrane is then exposed to UV light and if the gene is present there will be a fluorescent band
How is gene probing done as part of a DNA microarray
A DNA microarray is a glass slide with microscopic spots of different DNA probes attached to it in rows
A sample of fluorescently labelled human DNA is washed over the array
If the labelled human DNA contains any DNA sequences that match the probes it will stick to the array
The array is washed to remove any DNA that hasn’t stuck to it
The array is then visualised under UV light any labelled DNA attached to a probe will show up
Any spot that fluoresces means that the person’s DNA contains that specific allele
Uses of screening using DNA probes
To help identify inherited conditions
To help determine how a patient will respond to a specific drug
To help identify health risks
Genetic councillors role
Advising patients and their relatives about the risks of genetic disorders
Advising patients about screening
Explaining the results of a screening
Help identify what type of mutation a person has
Help identify what treatment will be most effective and what preventative options are available
What is personalised medicine
Tailoring medicine to a person’s DNA or genotype this will be likely to make the treatment more effective and reduce risk
