DNA fingerprinting uses short fragments of DNA containing STRs or short tandem repeats to identify an individual as well as compare other DNA samples obtained. This is very useful in determining relationships (e.g. paternity, maternity) as well as in comparing DNA samples in the scene of the crime with persons contained within a database. This technology has changed law enforcement, forensics, medicine and modern identification techniques. It thus has the capacity to affect numerous lives, both in a positive and a negative way.
DNA fingerprinting uses biological samples, blood, hair or skin, to obtain DNA. The advent of polymerase chain reaction (a DNA amplification technique) allows the extraction of sufficient DNA from even the smallest amount of blood, semen or hair. A portion of this DNA is scanned for trademark base pairs and kept in a database containing DNA fingerprinting results. Deoxyribonucleic acid contains four base pairs: adenine, guanine, cytosine and thymine. These base pairs may occur in repeat patterns called short tandem repeats that can be distinguished with comparative ease. Samples between individuals can then be matched by comparing the presence of these short tandem repeats. The more closely related a person, the closer to 100% the match is. If two samples belong to the same person, then the match is statistically 100% (adjusted for percent error). This is useful when identifying unidentified corpses or when establishing presence in the scene of the crime. Several locations in a person’s genome can also contain trademark sequences that indicate a tendency for a particular disease. DNA fingerprinting helps identify the occurrence of a disease on a particular person by scanning the location where telltale STRs can be found.
DNA fingerprinting, for all its great applications, is simply a tool, albeit a powerful one. There are thus numerous pros and cons when talking about DNA finger printing.
DNA Fingerprinting Pros
DNA Fingerprinting has made identification and establishment of relationships easier. In crime scenes, even a small drop of blood can be stored in a database, and matched with existing entries in that database. This makes solving crime and establishing presence in the crime scene faster and more efficient.
The DNA is a highly resilient molecule. It does not denature easily, except with certain compounds and other specific environmental conditions. Thus a DNA sample can linger for quite a while, making them accessible for analysis in crime scenes discovered after a while.
DNA fingerprinting is also a very flexible, efficient and versatile process. With a few drops of blood, one can establish identity, location in a crime scene, paternity and other relationships.
DNA Fingerprinting Cons
It is the lingering presence of a DNA database that is the source of concern for civil libertarians. The ease with which a DNA sample can be obtained precludes the right of the person to actually consent to have their DNA tested. The DNA database contains not only DNA fingerprints for convicted criminals, but also from those proven innocent, patients in psyche wards and juvenile delinquents. Since DNA fingerprinting does not compare the whole genome, there is a very small probability that a match can occur by sheer chance.
The resilience and prevalence of DNA can also inundate a crime scene with extraneous DNA, especially if it is located in a public place, like a restroom or a bar. Human error can also play a part in confusing and labeling the DNA of one individual with that of another.
Even with these concerns, DNA fingerprinting remains a powerful tool in law enforcement and identification. Further advances in technique and procedure can only augment DNA fingerprinting’s positive points while rendering the negative ones less likely to occur.