Touch DNA

Last updated November 13, 2023

Touch DNA, also known as Trace DNA, is a forensic method for analyzing DNA left at the scene of a crime. It is called "touch DNA" because it only requires very small samples, for example from the skin cells left on an object after it has been touched or casually handled,^[1] or from footprints.^[2] Touch DNA analysis only requires seven or eight cells from the outermost layer of human skin.^[3] The technique has been criticized for high rates of false positives due to contamination—for example, fingerprint brushes used by crime scene investigators can transfer trace amounts of skin cells from one surface to another, leading to inaccurate results.^[4]^[5] Because of the risk of false positives, it is more often used by the defense to help exclude a suspect rather than the prosecution.^[6]

Method

Touch DNA relies on the STR analysis of cells collected off of objects.^[8] Upon collection, the cells' DNA is extracted, and 13 genomic locations that vary among individuals are assessed to confirm suspects or exonerate those that are innocent.^[9]

Notable use cases

United States

The duct tape found with the remains of Caylee Anthony was tested for the presence of touch DNA during the criminal case against her mother, Casey Anthony. Richard Eikelenboom testified for the defense that none of Caylee's DNA was found on the tape.^[10]
Touch DNA was introduced in the third trial of David Camm by the defense. The DNA profile of another man, Charles Boney, was found on a number of objects at the crime scene, including the panties of Camm's wife Kim and a fingernail that is thought to have broken off during the struggle. The DNA evidence aided in his acquittal of the murders.^[11]
In 2008, the parents of JonBenet Ramsey were cleared as suspects in her 1996 murder following an analysis of touch DNA on her clothing. The family had long been the target of suspicion by the media, the police, and the public in the death of 6 year old JonBenet. The DNA also cleared John Mark Karr, a teacher who was arrested for the murders in 2006. The DNA was determined to belong to an unknown male. The case remains unsolved.^[12]
The prosecution used touch DNA to help build their case against James Biela for the murder of Brianna Denison. Touch DNA was collected from the doorknob of the residence where Brianna was staying when she was abducted. A DNA sample obtained from panties found near the body was later matched to the touch DNA and to Biela himself.^[13]
In December 2012, a homeless man named Lukis Anderson was charged with the murder of Raveesh Kumra, a Silicon Valley multimillionaire, based on DNA evidence. Anderson was drunk and nearly comatose, hospitalized, under constant medical supervision, the night of the murder. Anderson's DNA was accidentally transferred to the crime scene by paramedics who had arrived at Kumra's residence. The paramedics had treated Anderson earlier the same day—accidentally transferring Anderson's DNA to the crime scene hours later. The case was presented to the annual American Academy of Forensic Sciences meeting in Las Vegas, as a definitive example of a DNA transfer implicating an innocent person.^[14]
In December 2015, police officer Daniel Holtzclaw was convicted of 18 felony counts, charges stemming from allegations of sexual assault, based on Touch DNA found on one of the alleged victims.^[15]

Related Research Articles

DNA profiling is the process of determining an individual's deoxyribonucleic acid (DNA) characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding.

Forensic science, also known as criminalistics, is the application of science to criminal and civil laws. During criminal investigation in particular, it is governed by the legal standards of admissible evidence and criminal procedure. It is a broad field utilizing numerous practices such as the analysis of DNA, fingerprints, bloodstain patterns, firearms, ballistics, toxicology, and fire debris analysis.

<span class="mw-page-title-main">Killing of JonBenét Ramsey</span> Unsolved murder of an American child beauty queen

JonBenét Patricia Ramsey was an American child beauty queen who was killed at the age of six in her family's home in Boulder, Colorado. A long handwritten ransom note was found in the home. Her father, John, found the girl's body in the basement of their house about seven hours after she had been reported missing. She had sustained a broken skull from a blow to the head and had been strangled; a garrote was found tied around her neck. The autopsy report stated that JonBenét's official cause of death was "asphyxia by strangulation associated with craniocerebral trauma". Her death was ruled a homicide. The case generated worldwide public and media interest, in part because her mother Patsy Ramsey, a former beauty queen, had entered JonBenét into a series of child beauty pageants. The crime is still considered a cold case and remains an open investigation with the Boulder Police Department.

John Bennett Ramsey is an American businessman, author, and father of JonBenét Ramsey, who was murdered in his Boulder, Colorado, home on December 26, 1996.

Hair analysis may refer to the chemical analysis of a hair sample, but can also refer to microscopic analysis or comparison. Chemical hair analysis may be considered for retrospective purposes when blood and urine are no longer expected to contain a particular contaminant, typically three months or less.

Trace evidence is created when objects make contact, and material is transferred. This type of evidence is usually not visible to the eye and requires specific tools and techniques to be obtained. Due to this, trace evidence is often overlooked, and investigators must be trained to detect it. This type of evidence can link a victim to suspects and a victim or suspect to the crime scene.

Forensic identification is the application of forensic science, or "forensics", and technology to identify specific objects from the trace evidence they leave, often at a crime scene or the scene of an accident. Forensic means "for the courts".

<span class="mw-page-title-main">Patsy Ramsey</span> American beauty pageant winner (1956–2006)

Patricia Ann Ramsey was an American beauty pageant winner who won the Miss West Virginia Pageant at age 20 in 1977. She was best known as the mother of JonBenét Ramsey, a six-year-old child beauty pageant queen who was found dead in her family's home in Boulder, Colorado, on December 26, 1996.

The Forensic Science Service (FSS) was a government-owned company in the United Kingdom which provided forensic science services to the police forces and government agencies of England and Wales, as well as other countries.

Barry Charles Scheck is an American attorney and legal scholar. He received national media attention while serving on O. J. Simpson's defense team, collectively dubbed the "Dream Team", helping to win an acquittal in the highly publicized murder case. Scheck is the director of the Innocence Project and a professor at Yeshiva University's Benjamin N. Cardozo School of Law in New York City.

Forensic biology is the use of biological principles and techniques in the context of law enforcement investigations.

A crime laboratory, often shortened to crime lab, is a scientific laboratory, using primarily forensic science for the purpose of examining evidence from criminal cases.

<span class="mw-page-title-main">Wrongful conviction of David Camm</span> American police officer wrongfully convicted of murder (born 1964)

David Ray Camm is a former trooper of the Indiana State Police (ISP) who spent 13 years in prison after twice being wrongfully convicted of the murders of his wife, Kimberly, and his two young children at their home in Georgetown, Indiana, on September 28, 2000. He was released from custody in 2013 after his third trial resulted in an acquittal. Charles Boney is currently serving time for the murders of Camm's wife and two children.

Low Copy Number (LCN) is a DNA profiling technique developed by the UK Forensic Science Service (FSS) which has been in use since 1999.

<span class="mw-page-title-main">Murder of Brianna Denison</span> Murder of American student

Brianna Zunino Denison was a college student who was abducted on January 20, 2008, from a friend's house in Reno, Nevada. Her body was discovered on February 15, 2008, in a field near a Reno business park after being raped and murdered. A man named James Biela was convicted of the murder.

Rape investigation is the procedure to gather facts about a suspected rape, including forensic identification of a perpetrator, type of rape and other details.

Forensic serology is the detection, identification, classification, and study of various bodily fluids such as blood, semen, saliva, and urine, and their relationship to a crime scene. A forensic serologist may also be involved in DNA analysis and bloodstain pattern analysis. Serology testing begins with presumptive tests which gives the analyst an indication that a specific bodily fluid may be present, but cannot completely confirm its presence. Following the presumptive tests, confirmatory tests are done on the same sample to confirm what the unknown substance actually is.

Werner Uri Spitz is a German-American forensic pathologist who has worked on a number of high-profile cases, including the investigations of the assassinations of president John F. Kennedy and Martin Luther King Jr. He also testified at the trials of Casey Anthony and Phil Spector, the 1996 civil trial against O. J. Simpson, and consulted on the investigation of JonBenét Ramsey's 1996 death.

Investigating Innocence is a nonprofit wrongful conviction advocacy organization that provides criminal defense investigations for inmates in the United States. Investigating Innocence was founded in 2013 by private investigator Bill Clutter to assist nationwide Innocence Project groups in investigating innocence claims. "Once we have a case that meets our criteria, we'll put private investigators to work on it. A lot of these cases need investigators," said Kelly Thompson, executive director of Investigating Innocence. Prior to his work on Investigating Innocence, Clutter was one of the founders of the Illinois Innocence Project. Investigating Innocence also has a board composed of exonerees that reviews incoming cases.

DNA profiling is the determination of a DNA profile for legal and investigative purposes. DNA analysis methods have changed countless times over the years as technology changes and allows for more information to be determined with less starting material. Modern DNA analysis is based on the statistical calculation of the rarity of the produced profile within a population.

References

↑ Low Copy Number DNA Archived 2011-01-03 at the Wayback Machine – nfstc.org
↑ https://pgl.soe.ucsc.edu/footprint.pdf ^{[ bare URL PDF ]}
↑ "What is touch DNA?". Scientific American. 2008-08-08.
↑ Low Copy Number DNA and The Forensic Institute Archived 2012-09-12 at archive.today
↑ Silverman, Mike (27 April 2014). "The strange case of the 'time travel' murder". BBC News. Retrieved 28 April 2014.
↑ Anderson, Chris (22 March 2012). "Tyson Case: Attorneys say use of touch DNA to show guilt is rare". Herald Tribune.
1 2 Disagreement on What to Call DNA Profiling with Really Small Samples Confuses Courts – Penn State University
↑ Cavanaugh, Sarah E.; Bathrick, Abigail S. (2018). "Direct PCR amplification of forensic touch and other challenging DNA samples: A review". Forensic Science International: Genetics. 32: 40–49. doi:10.1016/j.fsigen.2017.10.005. PMID 29059581.
↑ Houck, Max; Houck, Lucy. "What is touch DNA?". Scientific American.
↑ Hayes, Ashley (21 June 2011). "Prosecutors: Child of fellow Casey Anthony inmate drowned in pool". CNN.
↑ Kircher, Travis (8 October 2013). "David Camm Blog: Dr. Richard Eikelenboom and his Touch DNA". WDRB.
↑ "DNA clears JonBenet's family, points to mystery killer". CNN. 10 July 2008.
↑ Mikkilineni, Rupa (2 December 2008). "Tip line played key role in cracking cold case". CNN.
↑ Smith, Peter Andrey (2016). "When DNA Implicates the Innocent". Scientific American. 314 (6): 11–12. Bibcode:2016SciAm.314f..11S. doi:10.1038/scientificamerican0616-11. PMID 27196827.
↑ Leary, Mary (2017). "Touch DNA and Chemical Analysis of Skin Trace Evidence". William & Mary Bill of Rights Journal.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[1] Low Copy Number DNA Archived 2011-01-03 at the Wayback Machine – nfstc.org

[2] ttps://pgl.soe.ucsc.edu/footprint.pdf ^{[ bare URL PDF ]}

[3] "What is touch DNA?". Scientific American. 2008-08-08.

[4] Low Copy Number DNA and The Forensic Institute Archived 2012-09-12 at archive.today

[bbcn-5] Silverman, Mike (27 April 2014). "The strange case of the 'time travel' murder". BBC News. Retrieved 28 April 2014.

[6] Anderson, Chris (22 March 2012). "Tyson Case: Attorneys say use of touch DNA to show guilt is rare". Herald Tribune.

[law-7] 1 2 Disagreement on What to Call DNA Profiling with Really Small Samples Confuses Courts – Penn State University

[8] Cavanaugh, Sarah E.; Bathrick, Abigail S. (2018). "Direct PCR amplification of forensic touch and other challenging DNA samples: A review". Forensic Science International: Genetics. 32: 40–49. doi:10.1016/j.fsigen.2017.10.005. PMID 29059581.

[9] Houck, Max; Houck, Lucy. "What is touch DNA?". Scientific American.

[10] Hayes, Ashley (21 June 2011). "Prosecutors: Child of fellow Casey Anthony inmate drowned in pool". CNN.

[11] Kircher, Travis (8 October 2013). "David Camm Blog: Dr. Richard Eikelenboom and his Touch DNA". WDRB.

[12] "DNA clears JonBenet's family, points to mystery killer". CNN. 10 July 2008.

[13] Mikkilineni, Rupa (2 December 2008). "Tip line played key role in cracking cold case". CNN.

[14] Smith, Peter Andrey (2016). "When DNA Implicates the Innocent". Scientific American. 314 (6): 11–12. Bibcode:2016SciAm.314f..11S. doi:10.1038/scientificamerican0616-11. PMID 27196827.

[15] Leary, Mary (2017). "Touch DNA and Chemical Analysis of Skin Trace Evidence". William & Mary Bill of Rights Journal.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]