DNA Testing in Crime Scenes

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).

These newer methods are still used today and allow scientist to use skin, blood, semen, and hair to gather DNA (le.ac.uk). In 1988 DNA fingerprinting was used for the first time in a criminal investigation. Timothy Spe... ... middle of paper ... ...eloped research that displays that as many as four percent of DNA matches in forensic laboratories have been in fault (legal-dictionary). Gene mapping is currently being used to identify genes that can put people at risk for illness and to help the development of new medicines. Scientists hope to use gene mapping to lead to advancement in medicines, the treatment to disease, and its aid in disease prevention.

DNA, The New Crime Investigator Abstract What is DNA? The scientific definition is “deoxyribonucleic acid, the biological polymer that stores the genetic information in all free living organisms. Two linear molecules entwine to form the double helix. Now that the definition has been stated, let’s now define what DNA means to a crime scene or case investigator. In the law enforcement business DNA has been introduce as a revolutionary and efficient accurate tool to solve and crack modern and cold cases.

“Traditionally, the term “fingerprint” refers to the patterns, which are highly characteristic for any human individual, of the ridged skin of the distal finger phalanges…’fingerprinting’ has also been used for the electrophoretic and chromatographic characterization of proteins and, more recently, of deoxyribonucleic acid (DNA) molecules” (2) DNA fingerprinting has become a big part of our criminal system. Being able to show that someone committed a crime due to DNA is straight out of a science fiction novel but today we do it. In order to understand what DNA Fingerprinting is we first must look at what DNA is. DNA stands for Deoxyribonucleic Acid; DNA is the blueprint for everything in the human body. DNA is a double stranded or a double helix molecule, which means it sort of, looks like a type of ladder, it is made of four nucleotides: Adenine, Cytosine, Guanine, and Thymine.

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. Like fingerprints, DNA is unique, with the exception of identical twins; no two people have the same DNA.

DNA fingerprinting, also known as DNA typing, is the analysis of DNA (deoxyribonucleic acid) samples through isolation and separation. This technique of identification is called “fingerprinting” because, like an actual fingerprint, it is very unlikely that anyone else in the world will have the same pattern. Only a small sample of cells is required to preform a successful DNA fingerprint. The root of a hair, a single drop of blood, or a few skin cells is enough for DNA testing. DNA fingerprinting has many uses, some of which include crime scene investigations and paternity cases.

Introduction Identification of an individual as the source of a DNA profile in a criminal case using the PCR method has become a reliable tool investigators use. The profiles generated for forensic purposes gives important information about the questions revolving around who’s DNA is found at a ... ... middle of paper ... ... amount of product from inhibited DNA. The samples will then be amplified using the ABI Prism 7000 and analyzed using the 3130 Genetic Analyzer. Statistics The proposed study data set is a repeated measurement of the same thing and can be described as ordinal data which describes categories with importance in order. The purification methods can be ranked from providing the most to least STR DNA data.

This arrangement contains information and instruction for the development of the body. DNA defines each of our individual characteristics therefore making it very unique. The “arrangement of these bases in each DNA molecule is different for everyone except identical twins” (Wilson, Foreman & Asplen, 1999) and this is the key to the importance of DNA evidence. DNA is everywhere in the body and remains the same and that makes DNA a very important biological evidence. The individualistic characteristic is a key feature of DNA that assists in solving... ... middle of paper ... ...ght crime, but funding sources can slow the process.

Having this information creates a better understanding of how forensic scientists use DNA to identify people when biological evidence exists. The structure of DNA may seem complicated, but the basic structure is that it is found in the nucleus. Deoxyribonucleic acid is a long molecule that contains organisms unique genetic code and this is in part why forensic scientists are able to identify people. According to Advancing Justice Through DNA Technology, "It is part of a genome and holds instructions for making all the proteins in an organism." (Lynch, 2014).

A DNA sample is run through the database by CODIS’ matching algorithm that searches the indexes against one another to generate matches according to how often base pairs, or “markers,” repeat in th... ... middle of paper ... ...of Justice, 1 Sept. 2011. Keiper L. More states use familial DNA as powerful forensic search tool. Reuters [Internet]. 2011 [cited May 16 2012]; N. page. Available from: http://www.reuters.com/article/2011/03/30/us-crime-dna-familial-idUSTRE72T2QS20110330.