Touch DNA

Touch DNA refers to low-level DNA from skin cells recovered from items which may result from direct handling or indirect transfer. In the past, the sensitivity of the STR Analysis methods available in the community was insufficient to obtain a DNA profile. However, due to improvements in the STR analysis methods, Sorenson Forensics routinely processes evidence for Touch DNA.

From property crimes to cold homicide cases, we generate DNA profiles from samples with limited amounts of DNA. We also specialize in generating profiles from difficult or degraded samples.

Some examples of evidence items that can be tested for Touch DNA* include:

• Ligatures
• Fingernail cuttings/scrapings
• Clothing that has been handled, such as pulling or tugging in a targeted area
• Swabbing from inside a car, steering wheel, gear shift or door handle
• Swabbing of guns and shell casings

*In reports and testimony we often use the term trace DNA to avoid implying how the DNA was deposited; see our explainer.