8.4.12 Genetic Fingerprinting

Steps in Genetic Fingerprinting

1. DNA Extraction:

• DNA is extracted from a biological sample (e.g., blood, hair, or saliva).

2. PCR Amplification:

• Specific VNTR regions of the DNA are amplified using Polymerase Chain Reaction (PCR) to produce enough DNA for analysis.

3. DNA Fragmentation:

• The amplified DNA is cut into fragments using restriction enzymes or left intact for VNTR analysis.

4. Separation by Gel Electrophoresis:

• The DNA fragments are separated by size using gel electrophoresis. Smaller fragments move further through the gel than larger fragments.

5. Visualisation:

• The separated DNA is transferred to a nylon membrane (Southern blotting) or visualised directly using staining methods.
• Probes complementary to VNTR sequences can be used to highlight specific patterns, which are displayed as distinct bands.

6. Analysis:

• The banding pattern forms a genetic fingerprint, which is compared against other samples.

Applications of Genetic Fingerprinting

1. Forensic Science:

• Used to match DNA found at crime scenes with DNA from suspects.

2. Paternity Testing:

• Confirms biological relationships by comparing the child's DNA with potential parents.

3. Medical Diagnosis:

• Identifies individuals at risk of genetic diseases or disorders.

4. Animal and Plant Breeding:

• Ensures genetic diversity or verifies pedigree in breeding programmes.

5. Conservation Biology:

• Studies genetic variation in populations to aid conservation efforts.