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Dna in criminal investigations research paper
Use of DNA in criminal investigations
Pros and cons of forensic in dna cases
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DNA testing has overthrown the way police collect evidence in a number of criminal cases, especially rape and murder and consequently had a large impact on many past cases. However there are many disadvantages to DNA testing, such as a challenge of accuracy, the costs of DNA testing and the possible misuse of DNA. The prospect of a national DNA database in Australia has been heavily criticised with complaints of invasion of privacy and stigma against those with terminal diseases.
Deoxyribonucleic acid, or DNA as it is most commonly known, is a strand of molecules found within the cell nucleus of all living things. It is called a “genetic fingerprint” because each is different to the other and everyone, apart from identical twins, have different DNA patterns.
To extract DNA from a human is a simple process; it can be extracted from body tissue, such as the scraping of the inside of the mouth, or through blood.
DNA testing was first used in a criminal case in the United Kingdom in 1987. DNA evidence in courts has been widely accepted since then and is seen as a reliable source, due to the high accuracy of the results. However many people disagree to the use of DNA results. Many question the accuracy of DNA evidence, as only DNA segments are used in databases in contrast to the entire DNA strand. The possibility of DNA testing being inaccurate is very low, however, except in cases of identical twins who posses the exact genetic makeup. DNA testing is also very expensive, and ...
DNA evidence should not be colvcslected from suspects as a matter of routine. To do so will cause unnecessary privacy intrusion; in the vast majority of criminal cases DNA evidence will contribute nothing to the investigation. Thus, it would not be appropriate for Parliament to give blanket authority to collect DNA samples from all persons suspected of indictable offences. DNA should also not be collected from a suspect if investigators have no DNA evidence with which to compare the suspect's sample. Nor would a DNA sample be necessary if the suspect admitted guilt.
DNA is the genetic material found in cells of all living organisms. Human beings contain approximately one trillion cells (Aronson 9). DNA is a long strand in the shape of a double helix made up of small building blocks (Riley). The repeat segments are cut out of the DNA strand by a restrictive enzyme that acts like scissors and the resulting fragments are sorted out by electrophoresis (Saferstein 391).
DNA (Deoxyribonucleic acid) is a molecule found in in the nucleus of all cells in the body which carries our genetic information. DNA is found in the form of chromosomes, with a total of 23 pairs in the human body1. DNA holds the genetic coding for all our characteristics, i.e. our eye colour, body shape, and how we interact with others on a daily basis.
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
Deoxyribo Nucleic Acid (DNA) is a chromosome found in the nucleus of a cell, which is a double-stranded helix (similar to a twisted ladder). DNA is made up of four bases called adenine (A), thymine (T), guanine (G), and cytosine (C), that is always based in pairs of A with T and G with C. The four bases of A, C, G, and T were discovered by Phoebus Levene in 1929, which linked it to the string of nucleotide units through phosphate-sugar-base (groups). As mention in Ananya Mandal research paper, Levene thought the chain connection with the bases is repeated in a fix order that make up the DNA molecu...
As the world gets older, our technology gets stronger. When it comes to criminal cases such as homicides, the blooming of technology can be ever in the investigators favor. With the Grim Sleeper case in Los Angeles, DNA technology became a wonderful tool for the investigators. In the United States, the first appellate court decision to admit DNA evidence was made in Florida in 1998, in subsequent years DNA evidence gradually became a regular feature of criminal cases (Lewis 2010.) Having the technology we have today, we can connect recent cases with cold cases. A break in technology for this case was the outstanding familial DNA testing. This happened when the “Grim Sleeper” returned.
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...
Most studies have shown that popular opinion holds that without a doubt national DNA databases have proved useful in criminal investigations (Wallace, 2006, pS27). The concept of a national DNA database has raised concern about privacy and human rights as seen through the scope of public safety. All of these concerns are elevated with databases include convicted, arrestee, innocent, and “rehabilitated” offenders (Suter, 2010, p339). Robin Williams of University of Duham (2006) asserts that:
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.
Before the 1980s, courts relied on testimony and eyewitness accounts as a main source of evidence. Notoriously unreliable, these techniques have since faded away to the stunning reliability of DNA forensics. In 1984, British geneticist Alec Jeffreys of the University of Leicester discovered an interesting new marker in the human genome. Most DNA information is the same in every human, but the junk code between genes is unique to every person. Junk DNA used for investigative purposes can be found in blood, saliva, perspiration, sexual fluid, skin tissue, bone marrow, dental pulp, and hair follicles (Butler, 2011). By analyzing this junk code, Jeffreys found certain sequences of 10 to 100 base pairs repeated multiple times. These tandem repeats are also the same for all people, but the number of repetitions is highly variable. Before this discovery, a drop of blood at a crime scene could only reveal a person’s blood type, plus a few proteins unique to certain people. Now DNA forensics can expose a person’s gender, race, susceptibility to diseases, and even propensity for high aggression or drug abuse (Butler, 2011). More importantly, the certainty of DNA evidence is extremely powerful in court. Astounded at this technology’s almost perfect accuracy, the FBI changed the name of its Serology Unit to the DNA Analysis Unit in 1988 when they began accepting requests for DNA comparisons (Using DNA to Solve Crimes, 2014).
Singer, Julie A. "The Impact Of Dna And Other Technology On The Criminal Justice System: Improvements And Complications."Albany Law Journal Of Science & Technology 17.(2007): 87. LexisNexis Academic: Law Reviews. Web. 10 Mar. 2014.
In 1893, Francis Galton introduced a remarkable new way to identify people ("Fingerprinting" pg 1 par 3). His observation that each individual has a unique set of fingerprints revolutionized the world of forensics. Soon, all investigators had adapted the idea to use fingerprints as a form of identification. Unfortunately, over the course of the past century, criminals have adapted to this technique and seldom leave their incriminating marks at the crime scene. Forensics specialists were in need of a new way to identify criminals, and DNA provided the answer. When it comes to genetic material, it is virtually impossible for a criminal to leave a crime scene "clean." Whether it is a hair, flakes of skin, or a fragment of fingernail, if it contains genetic material then it has potential to incriminate. However, there are still concerns regarding DNA fingerprinting. What are the implications of using these tests in a courtroom scenario? What happens when DNA tests go awry? It is debatable whether or not DNA fingerprinting has a place in America's court systems.
The amazing world of forensic science can help one to understand how important the methods of fingerprinting and blood testing is. For the past decade, a powerful criminal justice tool and topic referred as forensic DNA and fingerprinting has cleared suspects, exonerated individuals wrongfully accused or convicted criminals of a crime (Saferstein, 2015). DNA has been admitted into court for judges and juries to consider the scientific evidence when hearing a case. In the case of Cupp v. Murphy, the warrantless search of the scraping of blood from the fingernail of an accused murderer was upheld by the Supreme Court. It involved no medical risk nor the risk of destruction of the evidence or the suspect. It allowed forensic science to prove
DNA (deoxyribonucleic acid) is a self-replicating molecule or material present in nearly all living organisms as the main constituent in chromosomes. It encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. Simply put, DNA contains the instructions needed for an organism to develop, survive and reproduce. The discovery and use of DNA has seen many changes and made great progress over many years. James Watson was a pioneer molecular biologist who is credited, along with Francis Crick and Maurice Wilkins, with discovering the double helix structure of the DNA molecule. The three won the Nobel Prize in Medicine in 1962 for their work (Bagley, 2013). Scientist use the term “double helix” to describe DNA’s winding, two-stranded chemical structure. This shape looks much like a twisted ladder and gives the DNA the power to pass along biological instructions with great precision.