3.8.4.2 Differences in DNA Between Individuals of the Same Species can be Exploited for Identification and Diagnosis of Heritable Conditions

Question 1

What is a DNA probe?

Answer 1

A short, single stranded length of DNA with a label which makes it identifiable

Question 2

What are the two types of probes?

Answer 2

Radioactively labelled: identified by X-ray film that is exposed to radioactivity
Fluorescently labelled: emit light under certain conditions e.g. when bound to the target DNA

Question 3

How are DNA probes used to identify particular alleles of genes?

Answer 3

DNA probe is complementary to the base sequences of the DNA of the desired gene]
The DNA is separated into two strands
The two strands are mixed with the probe which binds to the complementary base sequence (DNA hybridisation)
The site of binding can be identified via the probe