Dr. Julie Valentine, a nursing professor at Brigham Young University, recently released new research that found skins cells can help develop a DNA profile in sexual assault cases when no bodily fluids are left.
The process is called touch DNA. It’s the collection of skin cells left behind on skin, clothing or other objects. Valentine began studying it after a case in 2011 when a young woman was violently assaulted and the only evidence left was where the victim had been touched.
“It was really this huge, ‘Aha groundbreaking' moment when we thought, all right in theory, we've thought maybe we could collect touch DNA in these cases, but then we saw an actual practice in real life cases,” she said.
The process was a fairly new concept in 2011 when Valentine began studying it. However, it has now been used for a couple of years in Utah.
Valentine's team has developed a standard form for Utah medical examiners and forensic nurses to use for the collection of cells when dealing with sexual assault cases. It’s become standard practice in Utah.
DNA profiles can be created using short tandem repeat or STR, which are used in CODIS — the FBI’s database — to identify and create those profiles. It’s seen as the gold standard for evidence collection because of its unique identifiable factors to the individual.
Valentine said with the advancements being made in DNA analysis, there is “less and less” genetic material needed to identify someone. She said it’s more likely for clothing to hold onto skin cells longer than on somebody's skin, but there’s still ongoing research about that.
Her research has found it is also more likely for men to leave more skin cells.
“Men shed a lot more DNA than women for the most part,” she said. “And usually it's men from about 18 to 45, which is oftentimes the age range of our perpetrators.”
Amy Lightfoot, the director for the state’s crime lab said touch DNA is dependent on the context of the sexual assault. She said the location is meaningful because of where the skin cells are left on the body.
Lightfoot also said this process can provide another chance for victims to get justice.
“It’s a really amazing thing to give back to somebody that has just survived an incident to know that, even if there aren't bodily fluids left behind,” she said. “There's still an opportunity to potentially identify the suspect.”
Valentine said she wants to continue to work and educate the public and law enforcement on touch DNA and she hopes to see it used more commonly nationwide.
