Methods of Fingerprinting

Fingerprinting is a useful part of the criminal justice system.

Fingerprinting has been utilized by law enforcement since the 1930s. The Free Dictionary defines a fingerprint as a print made by an impression of the ridges in the skin of a finger; this definition accurately describes conventional fingerprinting. A DNA fingerprint, on the other hand, cannot be changed or manipulated by defacing the fingertips. This method of identification is more dependable than conventional fingerprinting, because no two people have the same DNA, and a person's DNA never changes. DNA fingerprinting, which has been in use since the 1980s, involves examining the body's cells and tissues. DNA analysis has proven to be a very effective tool in the prosecution of criminals. DNA fingerprint examiners typically work for law enforcement or the FBI (Federal Bureau of Investigation).

Things You'll Need

• Radioactive probe

Instructions

1. Inspect the DNA molecules. The RFLP (Restriction Fragment Length Polymorphism) method is when DNA is examined for particular patterns. A radioactive probe is needed to perform this.

2. Magnify the DNA. The PCR (Polymerase Chain Reaction) method is when strands of DNA are amplified. This process requires less DNA and is helpful in crime investigations where there may only be small amounts of DNA present.

3. Utilize the STR (Short Tandem Repeat) method. This process is the most common and is similar to PCR because they both look at sections of the DNA which repeat certain information. STR measures the frequency of base pairs within a particular section of a DNA strand.

Tips & Warnings

• Analyzing DNA requires expertise. The smallest error could damage a criminal case.

References

• Fingerprinting: DNA Fingerprinting Methods
• National Health Museum: DNA Fingerprinting in Human Health
• Free Dictionary: Fingerprint