Medical Diagnosis

Question 1

What is a DNA probe?

Answer 1

A short, single stranded section of DNA that has a label attached to make it easy to identify

Question 2

What are the types of markers attached to DNA probes and how are they identified?

Answer 2

• Radioactive labels detected by X-rays
• Fluorescent labels detected by UV

Question 3

How is a DNA probes made?

Answer 3

• use DNA sequencing to determine the sequence of nucleotides in a specific gene

Question 4

How are DNA probes used?

Answer 4

• make a DNA probe which is complementary to a part of the target gene
• tested DNA from the sample is treated to separate the strands
• patients DNA and DNA probe are mixed and the DNA probe will bind (hybridise) to the patients DNA if the complementary sequence is present
• the DNA probe then emits radioactivity or fluoresces so it can be detected

Question 5

Why are DNA probes used in medical screening?

Answer 5

Enable screening for many different genes at the same time using microarrays

Question 6

Why is genetic screening important?

Answer 6

• can select appropriate treatment at an early stage
• help couples make decisions when planning for children

Question 7

What is the role of a genetic counsellor?

Answer 7

• explains meaning of test results
• discusses implications
• advises on next steps eg. Choosing the best treatment or that the allele found doesn’t mean that the person has the disease

Question 8

What are the issues with genetically screening?

Answer 8

• gives false positives or false negative results
• confidentiality from family and employers

Question 9

What is personalised medicines?

Answer 9

Tailored to an individuals DNA so that they receive the most effective medicines due to their personal responses