People who watched crime-based television shows understand that DNA evidence is not always noticeable at first glance. In fact, in some cases, it can be impossible to detect visually. Take semen, for example. In large amounts, seminal fluid is easy to detect. It leaves a noticeable crusty stain on most fabric. However, if that fabric is washed then the stain is gone. Presumably, the evidence is washed away. This is not the case necessarily. There are several methods forensic scientists use to find traces of semen to identify a male’s identity. The Acid Phosphatase Color Test is widely regarded as the most effective way to both locate and characterize a seminal stain.
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
DNA technology has been used as a means to identify perpetrators of rapes and murders with a very high degree of reliability. However, interpretation of the evidence can be problematic at times. This problem comes into play when there are mixed sample’s, partial profiles and with contamination of the evidence submitted. Mixed samples
Forensic DNA Phenotyping is a new and emerging field of forensic science. As it is so new, there is very little in terms of literature on this field, very little testing done on this type of identification, and few cases that have used DNA Phenotyping to assist in the investigation. The first documented case of DNA Phenotyping being used is in the early 2000s, so it has had under 20 years of research and experimentation with it. There are many weaknesses to the version of DNA Phenotyping that is available for use so far, but once there is more research done on it, and more experimentation with this new science, DNA Phenotyping could easily be a major tool to investigators around the world.
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.
I. Before the 1980’s, 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.
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.)
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.
If a wrongful conviction occurs nowadays, our greatest chance to prove that it is a wrongful convictions is with DNA
Because there are many different types of crimes, it is often difficult to find enough physical evidence to convict a person. For example, in rape cases there is usually only a small amount of physical evidence, so cases are based on word alone. Because of DNA testing we can now take samples from the victim and attempt to match the results with those of the suspect. Therefore, DNA is sometimes the only real way of determining the guilt or innocence of a suspect without having any witnesses. Since many rape cases are left unsolved, DNA testing is believed to be the most accurate way of keeping sex offenders off the street. Because of the growing trend of using DNA in rape cases especially, a company in Brooklyn now advertises a small flashlight-like device intended to be used to jab at attackers in order to collect a sample of his skin for later use (Adler). According to a study by Joseph Peterson, with the Department of Criminal Justice at the University of Illinois, DNA evidence does not have a major impact on the decision to either convict or acquit
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
“In 1984, a British geneticist named Alec Jeffreys stumbled upon one of our most important forensic tools: DNA fingerprinting. Since his “eureka moment,” the scientific technique has been used successfully to identify perpetrators of a crime, clarify paternity and exonerate people wrongly convicted” (Jones). DNA evidence, specifically simple-mixture, is the most accurate type of forensic evidence we currently have at our disposal, but even it is not infallible. Other types of forensic evidence are much less accurate, but unfortunately their use is still permitted in U.S courtrooms. Jurors may be misled by experts within the courtroom as well. These misconceptions about the accuracy of forensic science and the field in general lead to many problems in the courtroom.
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.
Due to the uniqueness of DNA it has become a powerful tool in criminal investigations
In the case for PSA screening, PCa is the leading internal malignancy in US men and the second leading cause of cancer death in American men. Early detection of prostate cancers offers the best chance of cure. The PSA blood test is the best chance of cure. Currently, the PSA blood test is the best currently available way to detect PCa and it is easy, safe and inexpensive. PSA test results is a piece of information, it is what doctors do with the information that becomes the issue. However, the great majority of PSA detected tumors have the histologic characteristics of clinically important cancers. Also, PSA detection has found tumors early advancing the diagnosis by Seeral years (5-13) and prostate cancer mortality rates in U.S have decreased by 4% (patho book) since 1992, which is 5 years after initiation of prostate screenings. The dilemma is over treating the clinically unimportant disease versus under
This paper examines Carrell et al’s research along with three other scholarly research articles to better understand the effects that the DNA recovered from a crime scene has on a particular case and the forensic science 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