DNA In Forensics

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.

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

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

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.

Basically, our DNA (deoxyribonucleic acid) is our genes, and every person, except for twins, are born with a different DNA profile and that is in a giant database, containing every DNA profile of every person in the world. DNA testing started in 1985 by scientist Alec Jeffreys and was first used to solve a crime a year later. Before 1985 DNA evidence could not be used in court because it wasn’t invented yet, this increased the number of wrongful convictions which would have been prevented using DNA analysis. However, DNA analysis can still be used to solve crimes that occurred prior to the invention of DNA analysis, with a sufficient amount of DNA to be analyzed of course, which is a very small amount. Only a small amount of DNA is needed to find out who it belongs to, it can be found in blood, saliva, finger residue, hair, skin, semen and more.

Due to the uniqueness of DNA it has become a powerful tool in criminal investigations

No two people, except identical twins, have identical DNA sequences, which makes DNA testing appealing to law enforcement. Two types of DNA testing include short tandem repeat and variable number tandem repeat. Short tandem repeat requires less DNA compared to variable tandem repeat, which is “useful when a sample has been degraded at the crime scene.” (“DNA Evidence”) Whilst DNA evidence is a useful weapon in solving crimes, it is not infallible; therefore, it needs to be used with caution, especially with partial DNA profile,

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 is one of the most important pieces of evidence that a criminal justice agent can use in a court of law. There ae slim to no crimes committed that doesn’t have some type of DNA evidence left behind. Some DNA evidence could be, but not limited to, fingerprints, blood, hair, and any other bodily fluids. DNA is known as Deoxyribonucleic Acid, and is one of two types of molecules that encode genetic information (Medicine.net, 2017). DNA is characteristically unique to each person individually, unless they are a twin. DNA dictates a person’s look such as their eye color, blood type, height, hair color, skin color, etc. With this genetic information, intense testing can be done to find who may be connected to the genetic makeup of each stand

Indeed DNA profiling has rapidly transform the field of forensics. DNA profiling is the scientific analysis of evidence for crime scene investigation and other legal proceedings. DNA profiling is mostly used by forensic scientists and crime lab technicians. To identify criminals and victims using trace evidence like hair or skin samples. To produce a DNA profile, scientists compare sequences in the genome that vary from person to person. The typical steps in DNA profiling are DNA samples are isolated from the crime scene, suspect, victims, or other evidence. The next selected sequences from each DNA sample are amplified (copied many times) to produce a large sample of DNA fragments. Finally the amplified DNA regions are compared using a gel. All together, these steps provide data about which samples are from the same individual and which sample is unique.

Considered one of the most reliable forms of evidence, in many criminal cases in DNA evidence. Since the 1980s, DNA analysis has continued to make steady progress as an adjunct to police investigations. DNA can be collected from blood, hair, skin cells, and other bodily substances. Similar to fingerprints, each individual has a unique DNA profile, but unlike that of fingerprints, only a miniscule amount of genetic material is needed to identify or eliminate suspects. However, the reliability and accuracy of the use of DNA evidence in criminal trials in Australia is constantly being challenged. It raises the question as to whether or not the justice system has been placing too much faith in DNA evidence. Although it has the power to put criminals behind bars, over confidence and careless mistakes in the use of DNA evidence can lead to miscarriages of justice.

The origins of DNA were first discovered during 1857 by Gregor Mendel the "Father of Genetics”, whom was performing an experiment of genetics with pea plants, and would provide a basic foundation towards DNA and Genetics. Friedrich Miescher and Richard Altmann in 1869 were also part of the first people to discover DNA. While testing some sperm of a salmon, they discover a strange substance that they would name as "nuclein", which is known as DNA. This new form of "nuclein" (DNA) would be found to only exist in chromosomes. Frederick Griffith, a researcher, found the basis on DNA, from a molecule inheritance experiment involving mice and two types of pneumonia. His findings were that, when virulent disease is heated up (to kill) and is

Forensic science more than often deals with DNA fingerprinting being used as a technique to identify the offender of a crime in a particular case. The DNA fingerprint maybe RFLP, VNTR or STR. RFLP stands for Restriction Length Fragment Polymorphism. VNTR stands for Variable Number of Tandem Repeats. STR stands for Short Tandem Repeats. RFLP was the first DNA fingerprinting method. STR is currently the most popular fingerprinting method. These DNA fingerprinting techniques require restriction enzymes that are obtained from the bacteria, which are used to cut the DNA into smaller fragments at different loci. We also require agarose gel obtained from seaweed and nylon membrane or sheet. Electric current is required so that it can be passed on

This quote shows that DNA fingerprinting is a pretty accurate way of finding a suspect as it is almost impossible, given the odds of 1 in 64 billion, for two people who are not related to have DNA that would match up. The DNA would probably have to be contaminated for two unrelated people to have the same DNA, or even DNA that is similar enough to confuse suspects. This is one of the reasons that DNA fingerprinting is so useful. It is incredibly accurate as a form of identification as the genetic make-up of a person cannot lie. The results from DNA are pretty binary in terms of identification.