Also called genetic fingerprinting, DNA profiling and DNA typing, DNA fingerprinting is a technique of identifying a specific individual, rather than just a species, using the characteristics of his DNA (de-oxy ribonucleic acid). It was developed in 1985, by Sir Alec Jeffreys. It was commercialized in 1987. The technique is now used to test parentage, identify a body deformed beyond identification and to identify criminals and victims in a crime scene.
|DNA fingerprinting process (click to enlarge)|
Even though every person is unique, the vast majority of a person’s DNA, 99.9% to be exact, would match exactly that of other humans, making differences between two people rather difficult to find. It is the remaining 0.1% that determines the genetic difference between people. DNA fingerprinting primarily includes the collection and analysis of VNTR (variable number tandem repeats), unique sequences in the chromosomes. It uses a specific type of DNA sequence, called microsatellite, to make the identification a lot easier. 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 specific area, one can identify a person with relative ease.
The sections of DNA used in a DNA fingerprinting, even though highly variable, are passed down from parents to children. Although not all of the sections will be passed on, the children would have pairs only the parents have. By comparing a group of these sections, scientists can determine paternity and maternity. Owing to its high success rate, it is used in various parts of the world for paternity and maternity verification.
The DNA fingerprinting has a seminal role in forensics as well. In past comparing normal fingerprints used to be done to identify a person, which required obtaining distinguishable fingerprints of him. However, since all of the DNA sections are contained in every cell of a body, a person can be identified by tests on any piece of his body, be it a strand of hair or a drop of blood. This method is used to identify a criminal or a victim in crimes. In case of victims, even if the body is disfigured past identification by normal means, DNA fingerprinting can be employed for it.
However, despite the wide acceptance and its increasing popularity, the DNA fingerprinting is also controversial due to the concerns over the ill-use of the DNA profile. Sometime its use in investigations comes under fire. There are also incidents where criminals even planted fake DNA evidence on their bodies.
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