DNA Forensic Science

In McClure, Weisburd and Wilson (2008) summary article arguing that in addition to bench science, field experimentation involving forensic methods is key to assess the utility of various methods to solve crimes. The study reflected that there is a need for more research into many aspects of forensic science, criticizing the strength of scientific evidence that’s collected at a crime scene and interpretations of most forensic methods while omitting DNA testing. McClure et al’s (2008) explains that in sexual cases and homicides, the presence of DNA evidence actually increased the likelihood of prosecution and a conviction. According to the article “…the case of convictions, the odds-ratio for the presence of DNA evidence was 33.1 for sexual offenses and 23.1 for homicides” (McClure et al., 2008). Subsequently, the research shows that there was a consistent gradual decline in the national homicide rates that began in the 1900s and continued through into the 21st century. The decline of homicides in the US has dropped by from more than 90% in the 1960s to 62% in 2003. Even though this significant drop has occurred during the introduction of the new DNA testing

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

Human DNA is very similar to one another, but only about 0.1% is different from the next person. That 0.1% can tell a person’s eye color, hair color, and other physical features. DNA analyst are able to take a drop of blood, the size of a dime, and duplicate the number DNA found in that drop. With the ability to duplicate DNA, analysts can have a back-up, in the event a human error were to occur. Analyst can tell you exactly where your ancestors came from and the percentage that is still inside your DNA. DNA is a very powerful tool that can identify a murder if the individual left any blood, saliva, skin tissue, hair or semen. The education needed to be able make use of the DNA consists of a great deal of science classes.

From cases such as OJ Simpson to Chandra Levy, DNA profiling also called DNA fingerprinting or DNA typing has played a major role in the criminal justice system. The law enforcement community uses DNA profiling to rule out or identify suspects. Unlike hair microscopy, bite mark comparisons, shoe print comparisons, and firearm tool mark analysis, DNA typing has been developed through massive scientific research and has undergone meticulous scientific evaluation (Innocence Project). DNA is a foolproof method of identifying a perpetrator of a crime.

forensic identification technique today1. It is the case of analyzing and profiling a DNA sample

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.

The Australian Institute of Criminology has produced documentations explaining “the technique of ‘DNA identification’ compares the DNA of two bodily samples to ascertain whether or not they came from the same human being. Identity of DNA in the cells across both samples implies that the samples are derived from the same person (or identical twins); non-identity implies different human sources.”

through comparison with the DNA database. It can also be compared to other crime scene

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.

Evidence 3: DNA profiling is less intrusive. The best way of retrieving a DNA sample is by using either blood, saliva, or hair. For example, if you happen to be in a situation where your town is taking DNA samples to help solve a crime, that would be the best way to go. This way you are helping but also giving less information for the better.

DNA profiling technologies have had a considerable impact on how forensic science and criminal investigation have been understood, carried out, and regulated in the last 25 years. Current methods of forensic DNA profiling (known also as DNA fingerprinting and DNA typing), based on Polymerase Chain Reaction (PCR) amplifications of a varying number of Short Tandem Repeat (STR) loci found at different locations on the human genome, are regularly described as constituting the “gold standard for identification” in contemporary society. Prior to the implementation of PCR based extraction and amplification methods in the 1990’s, the initial uses of DNA fingerprinting (based on Multiple and Single Locus Probes) were largely confined to reactive

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

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).

Law Enforcement keep notes on arrests that have founded people innocent of crimes, and retention of an innocent person's DNA can be charge or otherwise, seen as a invasion of that person’s privacy and civil liberties. Dr. Alec Jeffrey, a former professor at the University of Leicester laboratory, consulted with his lawyers to develop the new type of technique called DNA profiling. His technique would prove that DNA fingerprinting (profiling) can individualize evidence compared to the blood typing. DNA profiling compares 13 standard STRs to form a profile. The analysis used by the scientists, uses PCR and STRs to profile an individual. It is highly unlike that two individuals’ identical numbers of repeats for all 13 STRs, will match, which DNA fails is hardly never due to a successful match of 385 million to 1. This makes DNA profiling the most accurate tool in Forensics.