Gene probes and medical diagnosis Flashcards
What are DNA probes?
Short strand of DNA that have a specific base sequence that’s complementary to the base sequence of a target allele
What are DNA probes used for?
They are used to locate specific alleles of genes or to see if a person’s DNA contains a mutated allele that causes a genetic disorder
What will a DNA probe bind (hybridise) to?
The target allele if it is present in a sample of DNA
Name the two types of label that can be attached to a DNA probe to allow it to be detected
Radioactive
Fluorescent
What do you need to do first in order to produce a DNA probe?
Need to sequence the allele you want to screen for.
Then you use PCR to produce multiple complementary copies of part of the allele
What is DNA microarray?
A glass slide with microscopic spots of different DNA probes attached to it in rows which can screen lots of genes at the same time
Describe how a DNA microarray is made and used
- a sample of fluorescently labelled human DNA is washed over the array
- if the labelled human DNA contains any DNA sequences that match any of the probes it will stick to the array
- the array is washed to remove any labelled DNA that has not stuck to it
- the array is the visualised under UV light and any labelled DNA attached to a probe will show
- any spot that is fluorescent means that the person’s DNA contains a specific allele
What 3 ways can screening using DNA probes be used to do?
- help identify inherited conditions
- help determine how a patient will respond to specific drugs
- help identify health risks
What is genetic counselling?
Giving advise to patients and their relatives about the risks of getting genetic disorders.
What does genetic counselling involve?
It involves advising people about screening and explains the results of screening.
What can screening help with?
Screening can help identify if someone is the carrier of a mutated allele, the type of mutated allele and the most effective treatment.
How can genetic counselling be used if the results of a screening are positive?
Genetic counselling is used to advise the patient on the options of prevention and treatment available
Why are some drugs more effective for some people than others?
Different people respond to drugs in different ways as your genes determines how you respond to drugs.
What are personalised medicines?
Medicines that are tailored to an individuals DNA.
Doctors will only prescribe the drugs that will be the most effective to you by using your genetic information to predict how you will respond to different drugs.
