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Persistence of Touch DNA for Forensic Analysis

NCJ Number
Date Published
June 2023
Publication Series

This article presents results from a rigorous analysis of complicating factors for "touch DNA" analysis, including low quantity of useable DNA, high variability in the amount of DNA left by touch, and DNA degradation, specifically answering the questions of how surface type, environmental condition, and exposure time can affect the stability of touch DNA evidence, and how touch DNA sample stability compares to control DNA samples.


Since the first use of DNA evidence in a criminal case in 1986, forensic scientists have considered biological material (such as hair, skin, and bodily fluids) to be relatively reliable physical evidence. While early technology required a substantial amount of biological material to extract enough DNA to build an individual profile for analysis, researchers have since discovered that they can obtain reliable DNA from more than just bloodstains or visible fluids; they can also obtain it from “touch DNA” that is left behind on surfaces or objects such as doorknobs, window latches, or steering wheels. Although touch DNA can be essential for forensic casework, it also comes with its share of issues. This article examines how surface type, environmental condition, and exposure time affect the stability of touch DNA evidence as well as how stability of touch DNA samples differ from control DNA samples.

Date Published: June 1, 2023