DNA in Criminal Investigation, Essay Example

DNA testing has become a common practice in criminal investigation.  DNA-typing technique has evolved from finger prints and blood type to so much more.  As researchers continue to study the map of chromosomes and discover new evidence, the level of personal characterization of human genome is evolving to extensive new levels.  “Forensic Analytical uses the most technologically advanced methods of criminal DNA testing, such as PCR-based DNA typing and short tandem repeats (STRs). “ (Criminal DNA Testing 2004) One of the newest DNA type technique is PCR, polymerase chain reaction, DNA typing.  This is a technique that allows biological evidence to be replicated from a small amount of DNA gotten from minute stains millions of times.

The new technique, PCR has benefits of the prior methods, RFLP (which is restriction fragment length polymorphism) analysis to include such factors as:  “The ability to analyze samples that are degraded by environmental factors such as heat, UV light, humidity and chemicals. The ability to analyze samples that have been exposed to microbial contamination.  A short preparation and analysis time of only a few days (versus weeks for RFLP). The ability to analyze “difficult” samples such as cigarette butts, envelope flaps, semen, hair, and bone.And finally, a powerful discrimination potential.” (Criminal DNA Testing 2004) PCR testing has been accepted most courts and legal systems because of its 99.9% accuracy.  CurrentlyPCR tests include Polymarker, short tandem repeat (STR) loci and DQA1.

Included in the new advancements of DNA typing, STR, which is the ability to analyze multiple genetic markers.  RFLP analysis was the former method, however STI loci increases the discrimination potential values. The DNA can then be detected by a capillary electrophoresis instruments after STR can label PCR products with fluorescent dyes. This instrument aids in reduces the ability of human error in handling and the interpretation of analytical data.  Some of the basic techniques in DNA typing test may be the same, but many factors have evolved to show more forensic information with less room for human error.

DNA is a vital part of criminal investigation today.   Some of the most common DNA found at a crime scene includes: Blood, Saliva, Perspiration, Hair, Teeth, Mucus, Fingernails, and Semen.  (Lawyer.com)  Since every individual has their own personal DNA, this allows law enforcement to connect a criminal to the crime based on the DNA found at the crime scene.   DNA can then be run through the CODIS, Combined DNA Index System.  This is a system funded by the Federal Bureau of Investigation that keeps DNA samples and information. Because of the high probability of accuracy, most of the time, DNA is considered adequate for prosecution and finding an individual guilty.  One of the only times that DNA has failed is in cases of bone marrow transplant recipients and identical twins.  DNA has proven to be identical and not to show the individual characteristics like in most other situations.

In 1996, the United States Department of Justice reports that the conviction of 28 men, that were convicted prior of violent sex crimes and murders were released based on DNA evidence. DNA has revolutionized the criminal justice system by providing evidence that can free the innocent, and tie the criminals to the actual crime. A decade ago, DNA testing was not permitted as viable evidence.  Now it is used to help identify perpetrators, rule out suspects, and use the smallest piece of DNA to tie a person to a crime. The Criminal Justice System has come a long way in a decade and it is still improving.  The more DNA is studied, the more they are realizing they can find out from it.  DNA is Criminal Investigation is extremely important and will continue to be utilized in its current forms and many more typing techniques as they come.

References

Criminal DNA Testing. (2004) Retrieved from: http://www.forensica.com/criminal-dna-testing.htm

Use of DNA in a Criminal Investigation. Lawyer.com. Retrieved from:                                                  http://criminal.lawyers.com/Criminal-Law-Basics/Use-of-DNA-in-Criminal-Investigations.html

Floyd, John. (2007) Impact of DNA Exonerations on the Nation’s Criminal Justice System. Retrieved from: http://www.johntfloyd.com/comments/may/11a.htm