Collection and Analysis of Evidence - Dna

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The use of typing and matching DNA to prove guilt of a crime suspect is now a very acceptable form of evidence in today’s courts of law. DNA testing is also used to prove the innocence of an individual that had previously been convicted of a crime even if years had passed since the crime was committed. “While genetic matches are extremely reliable in fingering criminals, they're virtually foolproof in exonerating the innocent. Some 240 convictions have been overturned in 33 states and the District of Columbia, according to the Innocence Project, a nonprofit advocacy group that works to free the wrongly convicted. Seventeen people have been released from death row after DNA evidence cleared them. (James, 2009) DNA testing is now not only just used in criminal cases. “As accuracy rises and costs drop, DNA analysis is becoming increasingly widespread. It's familiar to daytime-TV fans as the leading method to determine paternity; do-it-yourself tests are now sold at drugstores. Footballs used in the Super Bowl are marked with DNA to prevent counterfeiting; officials say there's just a 1 in 33 trillion chance of getting the pigskins' genetic sequence right.” (James, 2009)

Albert DeSalvo, the Boston Strangler, was a serial killer that raped and killed women in the Beacon Hill area of Boston in the 1960’s. He had never been confirmed as the Boston Strangler but had been incarcerated for other rapes that he committed. DeSalvo died while incarcerated and was never connected with the Boston Strangler murders. In 2009 and 2012, the city of Boston received government grants to conduct further investigations on “cold cases”. Evidence had recently surfaced to connect DeSalvo to one of the Boston Strangler’s victims so it was decided to conduct a DNA test on one of DeSalvo’s nephews and they got a hit. The match implicated DeSalvo and excluded 99.9 percent of the male population. But because a Y-STR profile is common to a group of male family members, it does not yield the more precise match to a particular individual available in other DNA tests. A Y-STR profile includes gene data that concentrates on the Y chromosome that is passed down from father to son. Every male in a paternal lineage has the same Y-STR DNA profile. This includes fathers, sons, brothers, uncles, nephews and a wider group of male relatives, even out to third and fourth cousins. With this information, the request to exhume DeSalvo’s body was granted and his actual DNA was tested. As it turns out DeSalvo was the Boston Strangler and proves that someone did not get away with murder. (Bulman, 2014)

Another cold case that DNA helped solve is the case of fifteen-year-old Linda Strait. She was abducted on September 26, 1982 and found the next day rape and strangled. The police had collected DNA evidence at the time of the crime but lacked the technology to use the evidence so the suspect, Arbie Dean Williams, was never formally charged. In March 2003, the DNA sample was tested and they matched. Williams, who was already serving a prison term for kidnapping, sexual assault and attempted murder of two eight-year-old girls, was formally charged on Aug. 18, 2004, with the murder of Linda Strait. (DNA Profiling Helps Solve 22-year-old Murder Case, 2004)

In conclusion, DNA is such a small part of a cell, which is in turn such a small part of a living organism, but it provides such a great amount of information. By matching DNA from evidence found at crime scenes with DNA collected from the suspects, guilty people can face the consequences of their actions while the innocent go free.

Works Cited

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National Institue of Justice Journal (273), 49.

DNA Evidence: Basics of Identifying, Gathering and Transporting. (2012, August 9).

Retrieved December 6, 2015, from National Institue of Justice: http://www.nij.gov/topics/forensics/evidence/dna/basics/pages/identifying-to-transporting.aspx

DNA Profiling Helps Solve 22-year-old Murder Case. (2004, October 4). Retrieved

December 6, 2015, from Government Technology: http://www.govtech.com/public-safety/DNA-Profiling-Helps-Solve-22-year-old-Murder.html

Hirby, J. (n.d.). History of Dna Testing In Criminal Cases. Retrieved December 6, 2015,

from The Law Dictionary Featuring Black's Law Dictionary Free Online Legal Dictionary 2nd Ed : http://thelawdictionary.org/article/history-of-dna-testing-in-criminal-cases/

James, R. (2009, February 19). A Brief History of DNA Testing. Retrieved December 6,

2015, from Time.com: http://content.time.com/time/nation/article/0,8599,1905706,00.html

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(2011). Campbell Biology - 9th Edition. San Francisco, Ca, USA: Pearson Education.

Understanding DNA Evidence: A Guide for Victim Service Providers. (n.d.). Retrieved

December 6, 2015, from National Criminal Justice Reference Service: https://www.ncjrs.gov/pdffiles1/nij/bc000657.pdf