Mitochondrial 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

DNA analysts have been profiling DNA since 1985. Then in 1998, the Combined DNA Index System became fully operational (“FAQs” 2010). CODIS’s three levels are the national level, the state level, and the local level. As September 2015, there is 14,740,249 DNA profiles in CODIS (“CODIS”, n.d.). Since everybody has different DNA, except identical twins, DNA analysts have been able to assists with investigator to determine between who is guilty and who is innocent. With some of their findings, they are able to exonerate individuals, who have been wrongfully convicted. Even though television may make DNA analysts’ life look simple on the screen, it is not. There is need for interest and education. Lastly, the actual job that entails for the DNA

. DNA profiling was first introduced to the criminal justice field in the mid-1980’s (DNA Initiative). DNA profiling was first described in 1984 by Alec Jeffreys, a geneticist at the University of Leicester in Britain (Aronson, 7). Dr. Jeffreys found that the genes that have no function, called “junk DNA” is where most of the variation is used for DNA profiling (Aronson 9). This region contains DNA sequences that repeat over and over again. Alec Jeffreys determined that the number of repeated sections at different locations vary from individual to individual (DNA Initiative). Consequently these repetitive regions became known as “variable number of tandem repeats” or VNTR’s.

DNA testing was first used in criminal prosecutions in 1985 and is now admissible in all states. (Hails, 184) Scientific and legal communities seem to universally accept the use of DNA as “good” evidence. Questions could arise regarding testing procedures. There are several testing methods that have been proven reliable and easily pass general acceptance and scientific validity tests. This is causes number of Daubert cases questioning DNA to decline. “In most cases, the tests that are used are well established and do not require a separate hearing” (Hails, 160)

(PCR), which isolates small fragments of DNA that have a high degree of variability from

III. Today I will discuss how DNA is tested, how reliable DNA evidence is, and contamination issues that could arise in DNA evidence.

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.

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

Identification means the steps needed in the analysis of unknown fluids to see what the substance is (“Biology,” 2016). Individualization determines whether a certain individual may or may not be the donor of a bodily substance by examining various markers (“Biology,” 2016). Processing biological trace evidence uses highly complex, automated technology to create a DNA profile that helps the investigators through the association of suspects to victims and to crime scenes (“Biology Services,” 2017). By using techniques such as polymerase chain reaction (PCR), forensic biologists can use variable markers found on the regular chromosomes (STR’s), the sex chromosomes (Y-STR’s) and within the mitochondrial DNA to distinguish one person’s DNA from another to a high degree of certainty (“Biology,” 2016). Forensic biologists are involved in assisting investigative agencies because police were led to Bernardo by a police sketch (“Serial Killers: Paul Bernardo and Karla Homolka,” 2013). The police took DNA (hair, blood and saliva) from Bernardo as a matter of routine to test it against specimens found on a rape victim’s clothing (Butts, n.d.). Forensic biologists were able to name the substances left on Kristen French’s body and match it to Bernardo’s DNA by processing it. On February 17th, 1995, Bernardo was arrested for the murders of Mahaffy, French, and the Scarborough rapes (Butts,

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.

Every day DNA technology becomes more advanced and innovative, for example can match the smallest amounts of biological evidence to a criminal offender. Future DNA techniques will be applied to existing systems and testing methods that will become more automated and will be more effective and less time consuming. Instead of waiting months of DNA results the future will provide instantaneous means for DNA profile development.

Another report from Turman, herarticle about the importance of DNA evidence to say in a strong and definite way that the offenders or to prove prisoner in criminal cases has arose in the media with the developing regularity over the last few years. Criminal justice professionals and the public behold that the forensic DNA technology is reforming

Recent advancements in DNA technology have improved law enforcement’s ability to use DNA to solve old cases. Original forensic applications of DNA analysis were developed using a technology called restriction fragment length polymorphism (RFLP). Although very old cases (more than 10 years) may not have had RFLP analysis done, this kind of DNA testing may have been attempted on more recent unsolved cases. However, because RFLP analysis required a relatively large quantity of DNA, testing may not have been successful. Similarly, biological evidence deemed insufficient in size for testing may not have been previously submitted for testing. Also, if a biological sample was degraded by environmental factors such as dirt or mold, RFLP analysis may have been unsuccessful at yielding a result (Turman).

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.