DNA crime case PDF

Preview

Summary

term 2...

Description

Murder of Tonya Ethridge McKinley Portfolio case focusing on DNA profiling. DNA is the record of a living organism’s genome. Deoxyribonucleic acid (DNA) is a long molecule that forms a unique genetic code called a genome. DNA, being a relatively robust molecule, survives well under a wide range (but not all) of environmental conditions; if it was labile, its use would be limited. DNA is naturally broken down as the cells in biological samples age, but if the conditions are appropriate, such as following rapid desiccation or freezing, DNA can survive for centuries Within the DNA of an individual, there are detectable patterns that are repeated several times that are characteristics of her or him. (What is DNA, 2016)

DNA profiling is employed in criminal investigations to gather biological proof. that can be connected to whom it originated from, either a victim or a suspect. Some sorts of biological proof are finger-marks, hairs, blood, saliva, semen, tissue samples and alternative bodily fluids. It is extremely unlikely that 2 unrelated individuals have an equivalent polymer profile, therefore if the proof generates a profile, and it matches the suspect's profile, then it is extremely unlikely that it comes from another source. The forensic use of blood types and hairs will eliminate suspects, however, only seldom results in the identification of the source. Originally, polymer identification was utilized in cases of rape and assault, however, because of its development, it is currently used more widely, for instance in crime scenes, in accidents and disasters with discoveries of dead bodies, burglary, vehicle theft. (Mountain,2016)

DNA profiling today is considered to the golden standard but it has its criticisms. The DNA samples can be easily contaminated and most important the profiles are compared and interpreted by humans which leaves room for bias and human error (Lynch, 2003). The probability that two individuals would have the same DNA fingerprint is less than one in 33 billion (Jeffreys et al,1985) but probability figures have caused controversy and have been debated in and out of courts (Lynch,

2003).

Tonya Ethridge McKinley was 23 years old and had an 18-month-old son waiting for her at home when she was killed in the early-morning hours of Jan. 1, 1985, in Pensacola. She was last seen alive around 1:30 a.m. at Darryl’s Bar & Grille in Pensacola, and in the early-morning hours of New Year’s Day, her body was found in an empty lot at the corner of Peacock Drive and Creighton Road, just one block off Scenic Highway. She was half-nude, strangled to death and sexually assaulted. Tonya's body was found shortly before 5 a.m. on New Year's Day by a family living on Peacock Drive who were taking their sick dog to an allnight veterinarian clinic.

Investigators collected semen, head hair and pubic hair from Tonya's body and the crime scene.

All the evidence was identified as being from the same person, but no matches were ever found in the national DNA database. (Adame, 2020) Over the last two years, the police have begun running profiles of DNA left behind against online databases where genealogy hobbyists and others post their DNA profiles in hopes of finding long-lost relatives. When the detectives found DNA that suggests someone was related to the killer, they made a family tree of that person looking for male relatives who lived near where the attack took place. (CBS News,2020) Thirty-five years later the police finally narrowed down the suspect. The suspect was identified as Daniel Leonard Wells, a 57-year-old man who still lived in the area. He was put under surveillance for several months before his arrest. (Ashley, 2020) Police surveillance teams then surreptitiously obtained his DNA from a discarded cigarette, which was tested and matched the DNA found at the crime scene. (Adame, 2020)

He was arrested on March 18th, 2020, for the murder of Tonya and held without bond. He faced charges of first-degree murder and first-degree sexual battery. While in custody, only two weeks after his arrest, he

hung himself in his jail cell days before his first court appearance. (Ashley, 2020)

Citation list: Adame, T. (2020, March 19). Pensacola police make arrest in 35-year-old cold case murder using familial DNA. Pensacola News Journal. https://eu.pnj.com/story/news/2020/03/19/pensacola-police-make-arrest-35-yearold-cold-case-murder/2869854001/. Adame, T. (2020, March 19). Pensacola police make arrest in 35-year-old cold case murder using familial DNA. Pensacola News Journal. https://eu.pnj.com/story/news/2020/03/19/pensacola-police-make-arrest-35-yearold-cold-case-murder/2869854001/. Ashley, M. (2020, October 6). Arrest Made in 35-Year-Old Cold Case in Pensacola, Florida. Medium. https://medium.com/the-true-crime-edition/arrest-made-in-35year-old-cold-case-in-pensacola-florida-84b6787a4e8b. CBS Interactive. (2020, March 20). Florida man arrested in 1985 killing of young mother after DNA found on cigarette. CBS News. https://www.cbsnews.com/news/tonya-mckinley-murder-daniel-wells-arrestedflorida-1985-killing-young-mother-dna-found-cigarette/. Cole, S. A., & Lynch, M. (n.d.). DNA profiling versus fingerprint evidence: more of the same? Genetic Suspects, 105–128. https://doi.org/10.1017/cbo9780511778193.007 Jackson, Andrew R. W., et al. Forensic Science, Pearson Education, Limited, 2016. ProQuest Ebook Central, https://ebookcentral.proquest.com/lib/gre/detail.action? docID=6400919. Jeffreys AJ, et al. (1985) Hypervariable 'minisatellite' regions in human DNA - The Human Genome Project: An Annotated & Interactive Scholarly Guide to the Project in the United States - CSHL Library & Archive Wiki. (n.d.). https://libwiki.cshl.edu/confluence/display/HGP/Jeffreys+AJ%2C+et+al.+ %281985%29+Hypervariable+%27minisatellite%27+regions+in+human+DNA. Lynch, M. (2003, May 15). God's signature: DNA profiling, the new gold standard in forensic science. Endeavour. https://www.sciencedirect.com/science/article/pii/S0160932703000681. Mountain, H. (n.d.). Chapter. 6 6 The analysis of deoxyribonucleic acid (DNA): DNA profiling. In Forensic Science: (Fourth Edition, pp. 169–229). Press, R. C. and A. (2020, March 19). Man arrested for New Year's 1985 murder of Tonya McKinley in Pensacola. WEAR. https://weartv.com/news/local/manarrested-for-new-years-1985-murder-of-tonya-mckinley-in-pensacola. The Public Engagement team at the Wellcome Genome Campus. (2016, January 25). What is DNA? Facts. http://www.yourgenome.org/facts/what-is-dna....