Have you ever felt like your cat might know a little more than you let it in? Well, you might be into something. New research suggests that our little feline friends can be surprising sources of clues when a crime is committed.
Specifically, a cat’s fur could hold enough DNA by someone who was around to serve as evidence of a passing encounter between the two. This may mean that although cats cannot be questioned, they may still be able to help identify perpetrators.
The new study is the first to look at how domestic pets contribute to DNA transfer, so there is a lot of work to be done. But it does represent a positive step towards the future collection of more comprehensive forensic evidence – which obviously will be really helpful police investigations.
“Human DNA collection should become extremely important in crime scene investigations, but there is a lack of data on companion animals such as cats and dogs in relation to human DNA transmission,” says forensic scientist Heidi Monkman of Flinders University in Australia.
“These companion animals can be of great relevance in assessing the presence and activities of a family resident, or any recent visitor to the scene.”
In recent years, DNA analysis technology has become so advanced that even the tiniest traces of genetic material can be relevant to a crime scene investigation. We messy humans leave our DNA everywhere. Even just brief contact with something can transmit traces of our genetic material. So-called tactile DNA alone is not sufficient to positively identify a suspect, but it can be used to support other lines of evidence, or exclude people.
Touching DNA obtained from a surface does not necessarily require a person to touch that surface. It can be transmitted by a number of means, in cells of the skin or hair that are swept away from a passing object, for example. This is where household pets may play a role.
So Monkman and fellow Flinders University colleague Maria Juray, an experienced crime scene investigator, teamed up with forensic scientist Roland van Orchot of Victoria Police’s Forensic Services Division in Australia to see if they could extract human-readable DNA traces from domestic cats.
Their study was conducted on 20 cats from 15 families. In the homes of the study participants, the researchers scanned the fur on the right side of each cat twice, and collected DNA samples from most of the human study participants (one of whom was a minor child who was not sampled). Cat swabs and human DNA samples were then processed.
In addition, the residents of the house filled out questionnaires about the daily behavior and habits of the cats. This included the number of times the cat was touched and by whomever in the house.
Detectable levels of DNA were found in 80 percent of cat swab samples. For all cats, there was no significant difference between the amount of DNA present, the time since human last contact, or the length of the cat’s hair.
The team was able to create DNA profiles Of the 70 percent of the cats in the study It can be interpreted well enough to relate to a human being. Most of the DNA was from people in the cat’s same household, but in six of the cats, only unknown human DNA was detected.
Two of those cats spent so much time in the crib that their DNA wasn’t sampled, which may explain some of the “fuzzy” results. The source of the unidentified DNA on the remaining four cats is unknown. None of the households had visitors for at least two days prior to sampling.
One case was particularly interesting: a family of two cats and two people. One of the cats, a paternal hairless, carried the DNA of an unknown third human. The other cat, the short-haired Vortex, did not. Both cats have reacted equally With people in their homes.
Possible sources could include direct transfer of DNA from a human, such as by patting, or by a cat cleaning contaminated surfaces. The DNA may also have survived from the last time the cat had contact with a visitor.
“How this DNA is transmitted to the cat and whether it persists in them is unknown,” the researchers wrote.
“More research is needed on the transfer of human DNA to and from cats, the persistence of human DNA on cats and what may influence varying levels of DNA present in cats such as behavioral habits, and their owners’ disposal status.”
Or maybe that’s what the cat wants you to think…
The search was published in International Forensics: Genetics Supplement Series.
#Scientists #cats #harbor #DNA #crime #scenes