DNA Analysis In Criminal Investigation

This paper explores deoxyribonucleic acid (DNA) collection and its relationship to solving crimes. The collection of DNA is one of the most important steps in identifying a suspect in a crime. DNA evidence can either convict or exonerate an individual of a crime. Furthermore, the accuracy of forensic identification of evidence has the possibility of leaving biased effects on a juror (Carrell, Krauss, Liberman, Miethe, 2008). This paper examines Carrells et al’s research along with three other research articles to review how DNA is collected, the effects that is has on a juror and the pros and cons of DNA collection in the Forensic Science and Criminal Justice community.

DNA forensics is a division of forensic science that focuses on the use of genetic material in criminal investigation to answer questions pertaining to legal situations, including criminal and civil cases. Through DNA testing, law enforcement officers are able to identify human remains or the individual responsible for a crime. DNA testing is a highly advanced scientific process that involves replicating the human DNA sequence to create a genetic map of an individual. Because of its reliability, DNA testing has become a significant factor in criminal cases. However, it has also been identified as having the potential to violate privacy and constitutional rights. The DNA identification process consists of five stages. These five stages

(PCR), which isolates small fragments of DNA that have a high degree of variability from

Let’s start by defining what in fact is DNA analysis. According to the FBI’s crime lab, the DNA analysis process can take place when bodily fluid stains and other biological tissues are found on physical evidence collected from a crime scene (FBI DNA Casework Unit, 2016). The DNA testing results obtained from evidence samples are compared to DNA from reference samples collected from known individuals. Such analyses may be able to associate victims and suspects with each other, with evidence items, or with a crime scene (FBI DNA Casework Unit, 2016). The FBI and other national crime labs can conduct nuclear, Y-chromosome, and or mitochondrial DNA testing depending on the technology and funds appropriated to the unit. Smaller fielded units would probably not be able to do some testing which would result in them forwarding evidence or using other assets with greater capabilities.

investigations both past and present. It can be used to identify criminals when there is evidence

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

Therefore, DNA is one of the most common things a forensic technician looks for. Forensic technicians investigate crimes. There job is to look for physical evidence that will be collected and later analyzed. While working on an investigation the forensic technician may seem to be looking for a specific sample. It may be a blood sample or even a single drop of saliva. In some cases, clues may lead to a single fingerprint left behind to solving a crime. The suspect assuming he or she has wiped away all traces that would lead them to the crime scene. Never realizing what the suspect might have left behind. This may have seemed irrelevant to the forensic technician. Who is taking part in searching the crime scene. DNA left behind such as a strand of hair leads to a suspect. To the result it may be found in the carpet, or in any other type of clothing.

Before any release, there must be proper evidence showing that the accused had nothing to do with the crime. The introduction of the first person using DNA to prove his innocent was David Vasquez. In 1985, he was convicted, later in 1990; he was released due to DNA evidence (O’Leary, 2012). Since the Vasquez case, DNA testing has been a very powerful technique to use to prove a person’s innocence. A great reason for this is because victims are capable of lying and misidentifying.

There have been many incidents where cases have needed a solid prosecution in order to convict the defendant in a murder or rape case. This is where DNA Testing comes in to help. By taking a DNA test, a person can be found guilty or not guilty. If a person claims they have been raped there can be a sperm sample taken from the suspect in order to prove that he is guilty or not. In addition, in a murder case there can be blood taken from the suspect so they can tell of his innocence. There are several ways to determine whether a person is guilty or not by this method. Many cases have begun to use this method saying that it is foolproof. People say this is the method of the future of crime

DNA evidence is extremely helpful in criminal trials not only because it can determine the guilt of a suspect, but also because it can keep innocent people from going to jail. The suspect must leave a sample of their DNA at the crime scene in order for testing to occur, but DNA can be found in the form of many things such as semen, blood, hair, saliva, or skin scrapings. According to Newsweek, "thousands of people have been convicted by DNA's nearly miraculous ability to search out suspects across space and time… hundreds of innocent people have also been freed, often after years behind bars, sometimes just short of the death chamber" (Adler ). Though some may think it is a waste of time to go

This includes analyzing blood and body fluids and removing tissue samples for later testing. They help law-enforcement with investigative information by collect medical evidence, such as trace evidence and secretions, to document sexual assault; and to recreate how a person received injuries. Typical test performed or order by the forensic pathologist may include; X-ray, blood screening, urine analysis, and toxicology report. When finish the information gathered can

 Bloodstain patterns can reveal a great deal about position and movement during a crime.  It has managed to destroy self-defense arguments of suspects. Forensic value of blood In forensic science, blood has

Criminologists, usually Forensic scientists, collect DNA sources of semen, saliva, hair follicle, body cells, skin, and blood. They must always wear gloves, mask, and use disposable instruments. This help prevents the DNA being contaminated, to where it would not be useable. The collected samples must be bagged and label in envelopes but not plastic bags! Plastic Bags retain moisture that will damage DNA, another reason why DNA must be protected and label is that direst sunlight and weather condition may damage DNA.

DNA is deoxyribonucleic acid, which is found in almost all living things. DNA serves as a code for the creation and maintenance of new cells within an organism. Within humans, it is found in almost every cell. Although most of our DNA is found within the nucleus of our cells as nuclear DNA, a very small amount of our DNA is also found within the mitochondria as mitochondrial DNA. Because mitochondrial DNA is generally not used for solving crimes, for the purpose of this paper it will be disregarded.

Acid Phosphatase is an enzyme found in seminal fluid. It comes from the prostate gland (Johnson 2009). Typically, the more Prostatic Acid Phosphatase found in a sample of semen is a sign of prostate cancer. This is important because the Acid Phosphatase Color Test was once used to determine of a male had prostate cancer. It was later replaced by Prostate Specific Antigen, aka PSA. Forensic scientists still use this test to identify semen, however. In 1938, Gutman and Gutman reported increased levels of acid phosphatase in patients with metastatic prostate cancer (Taira, Merrick, Wallner, and Dattoli, “Reviving the Acid Phosphatase Test for Prostate Cancer”). It was later replaced by the Prostate Specific Antigen in 1971 (Taira, Merrick, Wallner, and Dattoli, “Reviving the Acid Phosphatase Test