Page 61 - Clinical Biochemistry

• To detect genetic polymorphisms among individuals, whole human genomic DNA isolated
from the individuals, digested with a restriction enzyme will show different pattern of bands
i.e different Restriction Fragment Length Polymorphisms (RFLPs).
• RFLPs are then transferred (or blotted) to a nitrocellulose filter (Southern blotting) and
examined.
• This phenomenon is called genetic polymorphisms.
DNA Fingerprinting (Genetic Fingerprinting or DNA Profiling)
• DNA Fingerprinting is known since 1985, when it was announced by its inventor, Sir Alec
Jeffreys.
• It involves the use of DNA restriction analysis to identify individuals.
Prof. Alec Jeffreys: Discoverer of genetic fingerprinting, 1984. University of Leicester, UK.
DNA fingerprinting uses a specific type of DNA sequence, known as a microsatellite, to make
identification much easier.

Figure 28: Prof. Alec Jeffreys

The Use of Microsatellites in DNA Fingerprinting:
• Microsatellites are short pieces of DNA which repeat many times in a given person's DNA.
• In a given area, microsatellites tend to be highly variable, making them ideal for DNA
fingerprinting.
• By comparing a number of microsatellites in a given area, one can identify a person
relatively easily.