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Dna in forensic science essay
Use of DNA fingerprinting in criminal justice
DNA helps solve crimes
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DNA Evidence and Analysis
According to legal dictionary, DNA evidence has become a major tool in the world of forensic science that has provided for the analysis of forensic evidence, biological material that makes up the genetic code of most living organisms. DNA analysis, also known as DNA profiling and typing, examines the biological material found in DNA as physical evidence such as blood, hair, semen, tissue, bones, teeth, or other bodily fluids that is found at a crime scene, and is essential to linking to or excluding someone from crime scene evidence (legal dictionary). McDonald & Lehman, (2012). Says in 1953, Rosalind Franklin, James Watson, Francis Crick discovered DNAs double helix structure consisting of two twisted strands of polymers held together by hydrogen bonds that form between the complementary base pairing of nucleotides: adenine, to thymine and cytosine to guanine. A discovery that led to questions about how DNA variability are differences in the arrangement of base pairs and is
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Differences that not only make individuals look different, but also give individuals a unique DNA pattern or profile and is the same in every cell throughout a person’s body except for twins (McDonald & Lehman, 2012). In 1985, Sir Alec Jeffreys a English scientist advanced DNA profiling (analysis) by developing (RFLP), a restriction fragment length polymorphism a technique used to determine variations of Tandon repeats patterns of two or more repeated nucleotides in DNA sequences (McDonald & Lehman, 2012). The resulting DNA fragments are repeated by electrophoresis producing a unique individual pattern. This process is said to be time consuming. DNA profiling was first used in the case of Colin Pitchfork, a United Kingdom resident who was convicted
Other evidence located within the grave consisted of a generic watch, two cigarette butts, a button, a washer and a shell casing. All of these could be analysed for finger prints and DNA. The cigarette butts would also show a serial number indicating the brand (shown in Figure 3), which can be useful if it is found a victim or offender smokes a particular type of cigarette.
However, before linking any kind of unique characteristics to human DNA, Jeffreys stumbled upon one of his first findings while experimenting with the genomes of rabbits when he discovered that eukaryotic DNA contained introns. Introns are non-coding sequences found throughout DNA. While maintaining a high interest in the study of introns, “Jeffreys sought to combine his recently acquired molecular biology experience with his interests in human genetics. ‘The first question we asked was, If you can see DNA restriction fragments, can you see variation between people in those fragments?’” (Zagorski,
CBS’s CSI: Crime Scene Investigation exploded into popularity when it aired in 2000, opening doors for the creation of other similar criminal investigative television shows involving forensic evidence such as Cold Case, Criminal Minds, and Bones. Many of these CSI-type shows present a murder or crime solved within an hour-long episode using forensic evidence conceived by glamorized CSI personnel and sometimes fabricated methodologies and technologies that only exist on television. Despite just being shows, one wonders whether these popular shows have skewered public perceptions about forensic evidence in real court cases and have impacted the outcome of court verdicts. The CSI Effect, explained by Kim, et all, was named after the television show
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). However, there are some drawbacks using the RFLP method in the forensic science community. The RFLP technique requires a large amount of DNA and must be of high quality and cannot be degraded (Jones). Forensic scientists and the law enforcement community determined a need for a DNA profiling method that could be used on smaller DNA samples. Thus, the RFLP technique has been almost entirely replaced by Polymerase chain reaction.
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.
The most important type of evidence is DNA. When DNA testing takes place, the samples are collected from the suspect and the crime scene. These evidences include hair, fingerprint, human secretions, blood, semen and other bodily fluids, are collected and sent to the lab for further investigation.
The criminal justice system has changed a lot since the good old days of the Wild West when pretty much anything was legal. Criminals were dealt with in any fashion the law enforcement saw fit. The science of catching criminals has evolved since these days. We are better at catching criminals than ever and we owe this advancement to forensic science. The development of forensic science has given us the important techniques of fingerprinting and DNA analysis. We can use these techniques to catch criminals, prove people's innocence, and keep track of inmates after they have been paroled. There are many different ways of solving crimes using forensic evidence. One of these ways is using blood spatter analysis; this is where the distribution and pattern of bloodstains is studied to find the nature of the event that caused the blood spatter. Many things go into the determination of the cause including: the effects of various types of physical forces on blood, the interaction between blood and the surfaces on which it falls, the location of the person shedding the blood, the location and actions of the assailant, and the movement of them both during the incident. Another common type of forensic evidence is trace evidence. This is commonly recovered from any number of items at a crime scene. These items can include carpet fibers, clothing fibers, or hair found in or around the crime scene. Hairs recovered from crime scenes can be used as an important source of DNA. Examination of material recovered from a victim's or suspect's clothing can allow association to be made between the victim and other people, places, or things involved in the investigation. DNA analysis is the most important part of forensic science. DNA evidence can come in many forms at the crime scene. Some of these forms include hair; bodily fluids recovered at the crime scene or on the victim's body, skin under the victim's fingernails, blood, and many others. This DNA can be the basis of someone's guilt or innocence; it has decided many cases in the twentieth century. As the times continue to change and the criminals get smarter we will always need to find new ways to catch them. Forensic science is the most advanced method yet, but is only the beginning. As the field of science grows so will the abilities of the
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...
What is DNA? The scientific definition is “deoxyribonucleic acid, the biological polymer that stores the genetic information in all free living organisms. Two linear molecules entwine to form the double helix. Now that the definition has been stated, let’s now define what DNA means to a crime scene or case investigator. In the law enforcement business DNA has been introduce as a revolutionary and efficient accurate tool to solve and crack modern and cold cases. It also has played major roles in courtrooms through out the nation on either proven guilt, or revealing the truth behind the innocence on the wrongly accused and convicted by our own court system. DNA has also brought justice to those who have been brutally victimized of rape and sexual abuse by atrocious conniving sex predators.
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.
DNA profiling is a process used to identify individuals. Usually we hear about law enforcement officials utilizing DNA testing to apprehend and eliminate individuals from a case. However, there are several pros and cons of DNA testing. This process helps “clear the name of the innocent” to help those who have been wrongfully accused of a crime. This evidence can also help those who have been accused of a crime and put behind bars. DNA testing proved to solve many cases that have went unsolved, this is better known as cold cases. In Illinois, Governor George Ryan in the year 1988 gave DNA testing to inmates who were on death row, which led to 13 of the 25 being cleared from death row. DNA evidence from the crime scene (even cases many years
DNA analysis has come a long way since the beginning of any type of testing. Before DNA analysis became was used, or even used a widely as it is now, it was harder for law enforcement agencies to identify suspects of crimes. Now DNA analysis testing can determine the DNA of an individual, or a family member. DNA analysis is the process in which genetic sequences are studied. There are several different ways to analyze forensic DNA. This has had a great influence on the accuracy and reliability of DNA profiling that is used so commonly today by law enforcement and medical practitioners. So as the years have passed they have become precise with the results. They have became so good that some would say that they are too good. The analysis of
Child exploitation and solicitation has become a matter that has plagued many children and continues to grow in the online environment due to children falling prey to online solicitation and exploitation In order to do this criminal evidence, digital forensics and cybercrime experts, involve online child exploitation and solicitation would be far more rampant than can be imagined. In all cases of online crime involving children, physical evidence needs to be collected. Since most predators of children tend to conceal their identity, the online medium is the perfect nesting grounds for these individuals. For this reason, digital forensic experts will subpoena a suspect’s digital data, to include, but not limited to computers and cellphones to
Crime today seems as if it keeps getting worse and worse, but without forensic science would we have been able to figure out some of the main details in some cases? Forensic science is any science used to help solve a case/mystery, which is very vital when it comes to criminal investigation research. While researching my project I discovered all the many tasks and difficulties that come with forensics.
DNA sequencing may be used along with DNA profiling methods for forensic identification and paternity testing. DNA sequencing has been applied in forensics science to identify particular individual because every individual has unique sequence of his/her DNA. It is particularly used to identify the criminals by finding some proof from the crime scene in the form of hair, nail, skin or blood samples. DNA sequencing is also used to determine the paternity of the child. Similarly, it also identifies the endangered and protected species.