DNA And Crime Scene Analysis

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

2. The millions of copies that are created from a meager amount of DNA assist the laboratory in generating a DNA profile that will be compared against the DNA profile of the suspect.

At first a collection of blood and sperm samples from anonymous donors which are then combined into a mixture. The mixture is subjected for DNA extraction using chloroform, phenol and water. Pure DNA is dissolved in water. It is subjected to an enzyme, restriction that cuts the DNA fragments. The short DNA fragments are treated with alkali to make sticky ends.

Beginning in the mid-1980s, the development of DNA analysis technology has revolutionised the field of forensic science within the criminal justice system. As the refinement of procedures and technology continues, even minute samples of biological material (including blood, saliva, semen and skin cells) are able to be analysed and used to link or acquit perpetrators of crimes. (Whitney, R n.d.)

Today in the crime world, DNA evidence is strongly accepted in solving crime cases. This is all based in part by allowing a crime laboratory to have a designated unit whose main goal is to analyze DNA evidence to aid investigators with positive outcomes in crime case solving. With that being said we are going to discuss the functions of a DNA unit within a crime lab as well as address the vital role these units play in solving crime.

DNA forensics can also narrow down suspect pools, exonerate innocent suspects, and link crimes together if the same DNA is found at both scenes. However, without existing suspects, a DNA profile cannot direct an investigation because current knowledge of genotype-phenotype relation is too vague for DNA phenotyping. For example, a profile from a first time offender that has no match in any database may give the information that the criminal is a left handed male of medium stature with red hair and freckles. It would be impossible to interview every man who fits that description. However, with available suspects, DNA forensics has many advantages over other forms of evidence. One is the longevity of DNA. Although it will deteriorate if exposed to sunlight, it can remain intact for centuries under proper conditions (Sachs, 2004). Because DNA is so durable, investigators can reopen old cases to reexamine evidence.

Deoxyribonucleic acid (DNA) has been used to analyze and prove innocence or guilt of suspects of crimes with great accuracy. DNA is part of everyday life. It is the heredity material in humans and almost all other organisms. While being part of an investigation. DNA has helped to solve crimes. There is a couple ways that DNA left behind can be tested to solve a crime. Either if the suspect has been caught and or had his or her DNA tested, or if he or she has left behind any biological evidence. Which then needs to be tested to see if it matches the DNA found in the crime scene to his or hers DNA. The result to this comparison may help establish if the suspect committed the 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

Safety: Risk Assessment file:///C:/Users/sharo/Desktop/School%20Work/2017/Science/Genetics/dna-extraction.pdf - Remember to put on gloves and a lab coat in case of any spills. - Make sure to obtain a test tube rack so that the test tubes will be safely used. - Keep separate the distilled water and methylated spirits, carefully using the

DNA Fingerprinting, also known as DNA Profiling, is a method used to identify a person using DNA patterns that are specific to him/her. 99.9% of DNA is identical in every human being, but .01% is enough to distinguish between people. It is most commonly used in criminal cases to link a criminal to his/her crime scene, but is also used for paternity/maternity tests, and immigration records. Usually a skin, hair, or body fluid sample is collected from a crime scene or criminal or test candidate, then DNA is extracted and cut using enzymes that recognize patterns in DNA and run through a gel by an electric current in a process called electrophoresis (Annely).

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.

What is DNA? Is it these winding strands that look like ladders or is it what gives a person blonde hair and blue eyes? Actually, DNA is both of these things. DNA is a person’s genetic makeup–their hereditary blueprint passed on by their parents. It is a part of almost every cell in the human body. In each cell, a person’s DNA is the same; it stays the same throughout their lifetime. DNA is found in skin tissue, sweat, bone, the root and shaft of hair, earwax, mucus, urine, semen, and vaginal or rectal cells. The DNA found in a person’s saliva is the same as the DNA found in their blood. Parts of the DNA determine our physical characteristics, such as eye and hair color, height, and bone structure, but the

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.

The science text of DNA: The key to solving crimes by Richard Platt, explains how doctors or officers use DNA to detect a murder. My two important details from the passage is “Extracting DNA” and “Imperfect Proof”, because this helps me determine how the DNA is being used. Next, one important idea from the story is extracting DNA. First DNA can be found in blood, saliva, and other body fluids and tissue.