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The importance of dna profiling criminal investigation
Use of DNA in criminal investigations
Implications of dna profiling
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DNA profiling has been one of the biggest advances in technology and science in the 20th century due to its efficiency in the identification of individuals. It is commonly used by forensics scientist for identification of suspects or individuals in crime scenes. DNA profiling as it is today, was developed by two independent studies in molecular biology that occur during the same period of time, in two different places, and by two different scientists. In 1985, Alec Jeffreys developed a technique called DNA fingerprinting, which has been known as DNA profiling. And Kary Mullis invented the polymerase chain reaction which is a biochemical technology in molecular biology used to amplify one single sample of DNA across many orders of magnitude generating millions of copies of an specific DNA sample.
Modern DNA profiling is called STR, which is a very sensitive technique that help CSI's to identify criminals. It is the process where a specific DNA pattern is obtained from a person or sample of any bodily tissue.
The typical patterns of genetic profiles are produced by electrophoresis of treated samples of DNA. This patterns may be called fingerprints. In criminal investigations, there are tested about 10 sites of the DNA. If the banding patterns produced by the tested DNA samples of a suspect in a crime, and the samples taken from the crime scene are the same, it is enough evidence for convicting a suspect and taking him to jail. The 99% of human DNA is exactly the same for all the people, even though, a single droplet of blood, or an eyelash collected in a crime scene, contains all the genetic information needed of every single person in the world, to convict a criminal. DNA profiling has have a huge impact in many things, from the...
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DNA is the blueprint of life. It stores our genetic information which is what is in charge of how our physical appearance will look like. 99.9% of human DNA is the same in every person yet the remaining .1% is what distinguishes each person (Noble Prize). This small percentage is enough to make each person different and it makes identifying people a lot easier when its necessary. DNA not only serves to test relationships between people it also helps in criminal cases. DNA testing in criminal cases has not been around for many years if fact it was not until the early 1990s when the use of DNA testing for criminal cases was approved and made available. By comparing the DNA of a suspect and that found in the crime scene a person can either be convicted of a crime or they can be exonerated. This method of testing gained more publicity in the 1984 case of Kirk Noble Bloodsworth a man who had been convicted of the rape and first degree murder of a nine year old girl in Maryland. His case was a milestone in the criminal justice system since it involved the use of new technology and it also raised the question of how many people had been wrongly incarcerated for a crime they did not commit.
PCR duplicates and increases the quantity of a DNA strand, which is beneficial to forensic scientists who are faced with little quantity of materials (Saferstein 394). The introduction of PCR-based testing in DNA analysis required scientists to switch to smaller targets that had the same repetitive variation (Jones). This is how short tandem repeats, the newest method of DNA typing, evolved. 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).
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. Using familial DNA searching for investigative purposes is a reliable and advantageous method to convict criminals.
One of society’s problems is that the wrong people are convicted of a crime they did not commit. None have more dire consequences on those than who are wrongly convicted of rape and murder. The punishment for these crimes are as harsh as possible to deter the crimes and when wrongly convicted, the wrong person gets punished while the true perpetrator gets away. In order to increase the chance of convicting the true perpetrator of the crime, the tools to find and convict criminals had to be refined. And it was refined due to extensive research into DNA. This research was done by Alec Jeffreys and Vicky Wilson, the research’s technician, and it found that in the massive amount of junk codes, there exists many repetitious codes that have copied so many times that it varies from person to person. (Ridley 132) This means that people can be identified with only their DNA from their hair, fluids, skin, etc. This discovery has led to convictions of rapists and murderers such as the Pickford case that Ridley wrote about. It has also led to the sentences of many wrongly convicted people to be retracted and this had led to the release of about 200 people known as the DNA 200. (Phelan) Now, most of the world keeps criminals’ genotype information in order to identify repeat offenders. In the United States, every state requires that every convicted
It was in 1984 when Alec Jeffreys, a British geneticist, discovered that specific sequences of DNA did not add to the function of a gene but were still constant throughout it. (Britannica). Jeffreys called these minisatellites and determined that each individual organism had a unique arrangement of minisatellites (Britannica). In the early uses of DNA fingerprinting, it was only used for identifying genetic diseases and disorders but people quickly realized that it could be used in many different areas of science (hubpages). Years after the discovery of DNA fingerprinting, it had been used to solve the first immigration case, the first paternity case, and even helped identify the first identical twins (le.ac.uk). The first methods of DNA fingerprinting were accurate, but you would have had needed to acquire a large amount of DNA. Over time, the advancement of science has led to major advances that formed the basis of DNA profiling techniques. 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...
DNA Timeline: DNA Science from Mendel to Today. (2014). Retrieved May 29, 2014, from http://www.dnai.org/timeline/
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. In 1966, scientists discovered a genetic code that made it possible to predict characteristics by studying DNA. This lead to genetic engineering and genetic counseling. In 1980, Organ was the first to have a conviction based off DNA fingerprinting and DNA testing in forensics cases became famous in 1995 during the O.J. Simpson trial (SMC History , 2011).
Forensic genetics has other applications . The " fingerprint " DNA represents a valuable tool for forensic science . As is the case with an ordinary fingerprint genetic fingerprint is unique to each individual (except identical twins ) . The determination involves the observation of specific DNA sequences which can be obtained from extremely small tissue samples , hair, blood or eventually left at the scene . As Fifty microliters of blood, semen or five microliters of ten roots of hairs are enough , and nozzles secretions and cells from the fetus . In addition to its use in the capture of criminals , especially rapists , the genetic fingerprints can be used to establish family relationships . People involved in the conservation of species use them to be sure that captive breeding is among individuals who do not belong to the same family .
Once a crime has been committed the most important item to recover is any type of evidence left at the scene. If the suspect left any Deoxyribonucleic acid (DNA) at the crime scene, he could then be linked to the crime and eventually charged. A suspect’s DNA can be recovered if the suspect leaves a sample of his or her DNA at the crime scene. However, this method was not always used to track down a suspect. Not too long ago, detectives used to use bite marks, blood stain detection, blood grouping as the primary tool to identify a suspect. DNA can be left or collected from the hair, saliva, blood, mucus, semen, urine, fecal matter, and even the bones. DNA analysis has been the most recent technique employed by the forensic science community to identify a suspect or victim since the use of fingerprinting. Moreover, since the introduction of this new technique it has been a la...
U.S. Department of Energy, Office of Science. (2009). DNA Forensics. Retrieved from Human Genome Project Information: http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml
Deoxyribonucleic acid (DNA) is an acclaimed extraordinary discovery that has contributed great benefits in several fields throughout the world. DNA evidence is accounted for in the majority of cases presented in the criminal justice system. It is known as our very own unique genetic fingerprint; “a chromosome molecule which carries genetic coding unique to each person with the only exception of identical twins (that is why it is also called 'DNA fingerprinting ')” (Duhaime, n.d.). DNA is found in the nuclei of cells of nearly all living things.
"Using DNA to Solve Crimes." U.S. Department of Justice: National Institute of Justice. (September 9, 2014). Web. 29 May 2015.
taken from the suspect has often been enough to charge a person with the offense
Over the years technologies used in the criminal justice system have continued to become more advance and more difficult for the average person to understand. One of these relatively new and advanced ways investigators are getting evidence is deoxyribonucleic acid also know simply as DNA. DNA is the building block to life; everything that has ever lived has had DNA. DNA is a blueprint for your body that determines everything about you. This is good because DNA is unique to every person for the exception of identical twins. The certainty that all DNA is unique is very high. DNA is found in all types of body fluids such as blood, skin, sweat, tears, semen, vaginal secretions, salvia, urine and hair. These are often left behind at different crime scene’s depending on the type of crime. For instance if you were investigating a homicide you could look for blood at the crime scene. Another example would be if you were investigating a rape, you could try and get a sample of semen or vaginal secretion. DNA can be found just about anywhere, the hard part is finding and collecting it. (Deoxyribonucleic Acid, 2014)
... middle of paper ... ... Retrieved December 29, 2013, from http://www.dnaforensic.org/index.html. What is Biotechnology? n.d. - n.d. - n.d.