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The Use of DNA in Forensics
DNA (noun) [deoxyribonucleic acid] first appeared 1944 : any of various nucleic acids that are usually the molecular basis of heredity, are localized especially in cell nuclei, and are constructed of a double helix held together by hydrogen bonds between purine and pyrimidine bases which project inward from two chains containing alternate links of deoxyribose and phosphate.
What is forensics?
fo*ren*sic [1] (adjective)
First appeared 1659
1 : belonging to, used in, or suitable to courts of judicature or to public discussion and debate.
2 : ARGUMENTATIVE, RHETORICAL.
3 : relating to or dealing with the application of scientific knowledge to legal problems *~ medicine* *~ science* *~ pathologist* *~ experts*.1
How are the two related?
DNA can be used to identify an individual. In relation to forensics, when there is a crime investigation and some proof is needed to back up the suspect DNA is usually the way that scientist deal with the situation. Specialized forensic scientists scan about ten DNA regions that vary from person to person and use the data to create a DNA profile for that individual. This is effective because there is a very small chance that another individual has the same DNA profile in the same set of regions.
DNA can be used for many other things besides for committing a suspect. It can also free a person wrongly accused of a crime, identify crime and catastrophe victims ,establish paternity and other family relationships ,detect bacteria and other organisms that may pollute air, water, soil, and food ,and even match organ donors with recipients in transplant programs .
How effective is DNA in identifying a person?
DNA identification must be used intellige...
... middle of paper ...
...to test for drug use.
Products of Conception-
When a teenaged girl has been impregnated by a relative or other adults the non-living product must be analyzed. As well as in a rape or anything resulting in pregnancy.
How did the forensic use of DNA start?
Alec Jeffreys , a geneticist at the University of Leicester in Britains Midlands,
started forensic use of DNA. He invented the techniques that took human identification from the laboratory to the courtroom in 1984. He called the process "DNA fingerprinting" which is not used by most forensic scientists because it can be misleading. He applied his techniques to an immigration case. A boy from Ghana wanted to emigrate to Britain, claiming his mother was already a resident. A DNA analysis showed that the two were in fact related and the Home Office put its stamp of approval on the new technology.
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.
. 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, there has been a large number of individuals released or convicted of crimes based on DNA left at the crime scene. DNA is the abbreviation for deoxyribonucleic acid.
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.
The Innocence Project, using DNA evidence, has gone back to past cases and exonerated innocent people when they were wrongly convicted. There may be many reasons that several people are wrongly convicted every year. However, there are 6 reasons deemed as the most important regarding wrongful convictions. These reasons are eyewitness misidentification, unvalidated or improper forensic science, false confessions or admissions, government misconduct, informants or snitches, and bad lawyering (understand the causes).
DNA fingerprinting, or sometimes known as DNA typing, is isolating and developing images of sequences of DNA to evaluate the DNA in an individual’s cells. DNA fingerprinting today is used for many different things in many different areas of science. In forensic science, DNA typing can determine which person did which crime by using blood or skin left at a crime scene. In medical science, patients can find out who their siblings, parents, or children are by using DNA fingerprinting (webmd).
DNA in forensic science has been around for a long time. DNA has had help in solving almost every crime committed. There have been a lot of crimes where people are raped or murdered and the person who did it runs free. Scientists can collect the littlest item they see at the scene, such as a cigarette butt or coffee cup and check it for DNA. People have spent years in jail for a crime they didn’t commit till DNA testing came into effect. People are getting out of jail after 20 years for a crime they didn’t commit, cause of the DNA testing. DNA has helped medical researchers develop vaccines for disease causing microbe. DNA has become a standard tool of forensics in many murders and rapes.
DNA analysis is a scientific process among the newest and most sophisicated of techniques used to test for genetic disorders, which involves direct examination of the DNA molecule itself (Lyman, 2014) . Today crime labs use mtDNA analysis. This type of analysis allows smaller degraded pieces of DNA to still be successfully tested (Lyman, 2014) . There are several steps taken when analyzing DNA in forensics. When testing scientists must first isolate the DNA so it is not contaminated and can't be used. Lab technicians the take small pieces of the DNA, conserving as much as they can encase they need to test again. Once testing is done the next step is determining the DNA test results and finally there is the comparison and interpretation of the test results from the unknown and known samples to determ...
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
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...
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).
This shape looks much like a twisted ladder and gives the DNA the power to pass along biological instructions with great precision. The scientific and medical progress of DNA has been immense, from involving the identification of our genes that trigger major diseases or the creation and manufacture of drugs to treat these diseases. DNA has many significant uses in society, health and culture today. One important area of DNA research is that used for genetic and medical research. Our ability to now diagnose a disease in its earlier stages has been greatly improved....
Forensic science includes all types of different science such as: physics, chemistry, biology, computer science and engineering to matter of law. A forensic scientist is a specialist in a field of science who applies their knowledge to the purposes of law. The job as a Forensic Scientist not only has many details and facts you have to remember but you also need items of evidence that are relevant in order to examine the scene correctly.