Question

Explain the steps involved in DNA finger printing technique.

Answer 1

The steps involved in DNA fingerprinting technique are:

1. DNA sample: A DNA sample to analyzed is first collected.

2. Extraction of DNA: DNA is then extracted from the sample by lysis method.

3. Digestion by restriction endonucleases: Using a specific restriction enzyme, the DNA fragment is cut at a specific site. This is done to obtain RFLP (Restricted Fragment Length Polymorphism).

4. Electrophoresis: Using gel electrophoresis, the DNA fragment of various sizes are obtained.

5. Denaturing DNA fragment: The gel containing DNA fragments are then immersed in NaOH solution. This will denature DNA into single-stranded DNA.

6. Southern blotting technique: This is performed to transfer single-stranded DNA from the gel onto the nitrocellulose membrane.

7. Hybridization: This DNA fragment is subjected to hybridization with a suitable DNA probe tagged with a radioactive substance.

8. Comparing the sample of the suspect with the evidence: Using X-ray films, the DNA samples showing radioactivity are compared.