In a medical description, fingerprints are the dermal ridges on the finger. It is a characteristic pattern of the peptide fragments of a protein under electrophoresis at a right angle, chromatography. The use of fingerprint identification can be traced back to ancient times. In ancient Babylonia and China, people put their thumbprints and fingerprints on clay tablets and seals as signatures. The idea that fingerprints are unique to individuals dates from the fourteenth century. A study in 1686 by Marcello Malpighi, identified that under a microscope, the fingerprints have a series of ridges and loops. Moreover, according to a physiologist, Jan Purkinje, there are nine different fingerprint patterns.
The human DNA
The deoxyribonucleic acid or DNA are chains of chemical compounds inside every cell in the human body that join permanent blueprints for life.
These chemical compounds are called bases, and there are 4 of them. They pair up with one another to form base pairs, and your DNA contains 3 billion of those couples.
The complete set of those compounds is called a genome, and over 99.9 % of everyone’s genome is precisely alike.
How DNA Fingerprinting works
Other terms for DNA fingerprinting include genetic fingerprinting, DNA typing, DNA profiling, genotyping, or identity testing in genetics.
It is a laboratory technique of isolating and identifying variable elements within the base-pair sequence of DNA (deoxyribonucleic acid).
The initial step is to obtain sample cells either from skin, hair, or blood, which contain DNA. The DNA will then be extracted from the cells and purified. The double-stranded DNA fragments will be sorted and subject to a blotting technique. Through autoradiography, fragments are exposed to DNA probes.
After a dark mark is formed at any point where a radioactive probe had become attached, the resultant pattern then is analyzed.
British geneticist Alec Jeffreys established this technique in 1984. He observed that specific sequences of highly variable DNA known as minisatellites, do not contribute to the functions of genes, and are repeated within genes. He also recognized that each individual has unique minisatellites, with the only exceptions being multiple individuals from a single zygote, such as in the case of identical twins.
Uses of DNA fingerprinting
The early use of DNA fingerprinting was in legal disputes.
Beginning in 1924, the Federal Bureau of Investigation (FBI) established a fingerprint repository through its Identification Division. It stored fingerprint cards in a central location. And over the next 50 years, they have collected over 200 million cards.
In 1991, the FBI developed the Automated Fingerprint Identification System (AFIS) with a computerized card system. It has helped eliminated duplicate fingerprints and made more accessible storage and sharing fingerprints data among law enforcement agencies.
The Integrated AFIS system (IAFIS) was introduced in 1999 in which a law enforcement official can request a set of criminal prints and get a response within two hours.
Fingerprinting applies to people applying for jobs in government offices, jobs handling confidential information, banking jobs, teaching jobs, law enforcement jobs, and any job involving security issues. The IAFIS stores civil prints as well as criminal prints.
DNA fingerprinting for paternity testing
As reflected in movies and TV shows, paternity issues are real. It has become a significant challenge to scientists and potential parents alike.
In the early twentieth century, researchers often resort to people’s ABO phenotypes. However, ABO blood group information is delimiting as it excludes potential fathers, rather than confirming a parental relationship.
Despite the consideration of Rh antigens, MN antigens, and HLAs, it still left significant error. Thus, with the dawn of DNA analysis and sequencing techniques in the 1980s and 1990s, scientists increasingly began to look at people’s genomes when questions of fatherhood arose.
The technique was proven useful. The current marker-based methods of analysis have yielded test results that are both 99.99% accurate and applicable in various settings.
With the ongoing advancement of DNA sequencing and analytical technologies, we will undoubtedly continue to see an increase in the utility of these tests and the availability of detailed genetic services to the general public.
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