DNA, or deoxyribonucleic exists in all living organisms, is self-replicating and gives a person their unique characteristics. No two people have the same matching DNA. There are many different forms of DNA that are tested for situations such as criminal. Bodily fluids, hair follicles and bone tissues are some of the most common types of DNA that is tested in crime labs today. Although the discovery of DNA dates back to 1866 when Gregor Mendel proved the inheritance of factors in pea plants, DNA testing is relatively new and have been the prime factor when solving crimes in general.
“Traditionally, the term “fingerprint” refers to the patterns, which are highly characteristic for any human individual, of the ridged skin of the distal finger phalanges…’fingerprinting’ has also been used for the electrophoretic and chromatographic characterization of proteins and, more recently, of deoxyribonucleic acid (DNA) molecules” (2) DNA fingerprinting has become a big part of our criminal system. Being able to show that someone committed a crime due to DNA is straight out of a science fiction novel but today we do it. In order to understand what DNA Fingerprinting is we first must look at what DNA is. DNA stands for Deoxyribonucleic Acid; DNA is the blueprint for everything in the human body. DNA is a double stranded or a double helix molecule, which means it sort of, looks like a type of ladder, it is made of four nucleotides: Adenine, Cytosine, Guanine, and Thymine.
Nowadays, DNA is a crucial component of a crime scene investigation, used to both to identify perpetrators from crime scenes and to determine a suspect’s guilt or innocence (Butler, 2005). The method of constructing a distinctive “fingerprint” from an individual’s DNA was first described by Alec Jeffreys in 1985. He discovered regions of repetitions of nucleotides inherent in DNA strands that differed from person to person (now known as variable number of tandem repeats, or VNTRs), and developed a technique to adjust the length variation into a definitive identity marker (Butler, 2005). Since then, DNA fingerprinting has been refined to be an indispensible source of evidence, expanded into multiple methods befitting different types of DNA samples. One of the more controversial practices of DNA forensics is familial DNA searching, which takes partial, rather than exact, matches between crime scene DNA and DNA stored in a public database as possible leads for further examination and information about the suspect.
DNA fingerprinting has many uses, some of which include crime scene investigations and paternity cases. A British geneticist, Sir Alec Jefferys, is credited with developing the technique of DNA fingerprinting on September 10, 1984. Alec Jefferys was attending Leicester University at the time of his development of this technique. Jefferys noticed the existence of certain sequences of DNA strands, or minisatellites, that do not help the function of a gene but are duplicated within the gene. Jefferys also concluded that every organism has a unique pattern of these minisatellites and that the only exception was identical twins or multiple individuals from a one egg.
From cases such as OJ Simpson to Chandra Levy, DNA profiling also called DNA fingerprinting or DNA typing has played a major role in the criminal justice system. The law enforcement community uses DNA profiling to rule out or identify suspects. Unlike hair microscopy, bite mark comparisons, shoe print comparisons, and firearm tool mark analysis, DNA typing has been developed through massive scientific research and has undergone meticulous scientific evaluation (Innocence Project). DNA is a foolproof method of identifying a perpetrator of a crime. Like fingerprints, DNA is unique, with the exception of identical twins; no two people have the same DNA.
The Evaluation of Forensic DNA Evidence. (accessed March 2014) 4. Gill P., et al. DNA commission of the International Society of Forensic Genetics: Recommendations on the evaluation of STR typing results that may include drop-out and/ or drop-in using probabilistic methods. Forensic Science International: Genetics 6 (2012) 679–688.
These newer methods are still used today and allow scientist to use skin, blood, semen, and hair to gather DNA (le.ac.uk). In 1988 DNA fingerprinting was used for the first time in a criminal investigation. Timothy Spe... ... middle of paper ... ...eloped research that displays that as many as four percent of DNA matches in forensic laboratories have been in fault (legal-dictionary). Gene mapping is currently being used to identify genes that can put people at risk for illness and to help the development of new medicines. Scientists hope to use gene mapping to lead to advancement in medicines, the treatment to disease, and its aid in disease prevention.
Alternately, there is equal concern for the efficiency and effectiveness of utilizing the CODIS program in criminal investigations, based on the overwhelming backlog of collected and unregistered samples. Since Deoxyribonucleic Acid (DNA) is the building block of all genetic material and its structure is unique and unchanging, it is a highly accurate method of identifying the origin, and the originator, of unknown DNA samples (National Human Genome Institute, 2011). DNA profiles are extracted from genetic and biological samples collected from crime scenes and potential suspects, and then compared against DNA profiles registered in CODIS. While attempting to determine the donor of the sample, a probability match percentage is generated. This technique is known as DNA fingerprinting.
This variation in patterns of DNA fragments found in human genetic lineages is called ‘restriction-fragment length polymorphism’(RFLP)." (Louis Levine, ?) Because each person, except for identical twins(which have the exact same DNA), is formed from two family lines the pattern of sizes of the fragments from an individual is unique and can serve as a DNA fingerprint of that person. These ‘fingerprints’ have became very important in identifying criminals in a number of violent crimes where the victims aren’t able to. Blood or semen stains on clothing, sperm cells found in a vaginal swab taken after a rape, or root hairs are all available for analysis.
In 1989 the National Research Council Committee on DNA Technology in Forensic Science was developed due to numerous scientific and legal issues (The Evaluation of Forensic DNA Evidence). The National Research Council’s key role was to analyze statistical and population genetic issues in the use of DNA evidence and review major alternative approaches to statistical evaluation of DNA evidence (The Evaluation of Forensic DNA, 50). Over the past fifteen years DNA profiling has made tremendous advancements and continuous improvements in the fight against violent