Cats may carry DNA from crime scenes, forensics find

Cats can be an important source of clues left at crime scenes, reports ScienceAlert. It is impossible to interrogate them, but they can help to detect the criminal: cat fur is able to retain enough DNA of a person who was nearby to be evidence of his presence at the scene. This conclusion was reached by experts in the field of forensic science from Flinders University in Australia.

Humans leave their DNA everywhere, and DNA analysis techniques have become so sophisticated in recent guides that they can detect the smallest traces of genetic material left behind in the most momentary contact. Sensory DNA obtained from a surface does not even require a person to touch it. It can be transported, for example, with skin cells or leave traces of its presence in the hairs of wool, which are fanned by the air flow from a person passing by. Sensory DNA may not be enough to positively identify a suspect, but it can be used to confirm or rule out leads.

In their study, the researchers used 20 cats living in 15 families. All animals were swabbed from the hair on the right side of the body, and DNA samples were taken from all owners. As a result, detectable levels of DNA were found in 80% of feline swab samples. At the same time, no relationship was found between the amount of DNA present and the time elapsed since the last contact with a person, or the length of the coat.

From the swabs of 70% of the cats, the scientists were able to generate DNA profiles detailed enough to link them to a specific individual. Most of the DNA came from people from the host families, but only unknown human DNA was found in six of the cats. The origin of this unidentified DNA remains unknown: none of the houses had had guests for at least two days before the swabs were taken. It is likely that the DNA could have been preserved since the last time the cat had contact with the guests.

The study is published in Forensic Science International: Genetics Supplement Series.