Forensic felines: How a single cat hair can help detectives solve crimes

LEICESTER, United Kingdom — There’s no more purr-fect getaway for criminals — all thanks to cats! Researchers from the University of Leicester explain that cat hair can serve as a key tool in solving crimes.

According to their findings, a single strand of cat hair can contain DNA that may connect a suspect to a crime scene or a victim.

With approximately 29 percent of United States households owning a cat, and these furry companions shedding thousands of hairs each year, it’s inevitable that traces of these feline residents linger in various places. This seemingly innocuous fact could prove to be valuable in forensic investigations.

While human perpetrators often take precautions not to leave their own DNA behind, cat hair can unwittingly carry its own DNA, potentially providing a crucial link between a suspect and a crime scene or victim.

DNA is Key for Forensics

DNA, or deoxyribonucleic acid, is the genetic material found in all living organisms. It is unique to each individual, with the exception of identical twins, and it can be used to identify individuals with a high degree of certainty. This makes DNA a key tool for forensics, the scientific field that uses evidence to solve crimes.

Forensic scientists can use DNA to identify victims and suspects, link crime scenes together, and exonerate the wrongly convicted. DNA can be found in a variety of biological materials, including blood, semen, saliva, hair, and skin cells. Even small amounts of DNA can be recovered and analyzed using modern forensic techniques.

In a recent paper, University of Leicester scientists detail a sensitive method that can extract maximum DNA information from a single cat hair.

“Hair shed by your cat lacks the hair root, so it contains very little useable DNA,” says study lead author Emily Patterson, a Leicester PhD student, in a university release. “In practice we can only analyze mitochondrial DNA, which is passed from mothers to their offspring, and is shared among maternally related cats.”

This limitation means that hair DNA cannot individually identify a specific cat, underscoring the importance of maximizing the information obtained from a forensic test. However, researchers discovered a new method that allowed them to determine the sequence of the entire mitochondrial DNA, making it approximately 10 times more discriminating than a previously used technique that examined only a short DNA fragment.

“In a previous murder case we applied the earlier technique but were fortunate that the suspect’s cat had an uncommon mitochondrial variant, as most cat lineages couldn’t be distinguished from each other,” explains study co-author Dr. Jon Wetton, from the university’s Department of Genetics & Genome Biology. “But with our new approach virtually every cat has a rare DNA type and so the test will almost certainly be informative if hairs are found.”

Mr. Win, whose hair DNA identified his missing mother. (credit: Jane Elliot)

The team put their method to the test in a real-world scenario involving a lost cat case. They matched DNA from the skeletal remains of a missing female cat with DNA extracted from hair found on her surviving male offspring.

“In criminal cases where there is no human DNA available to test, pet hair is a valuable source of linking evidence, and our method makes it much more powerful,” notes Mark Jobling, professor of genetics at Leicester. “The same approach could also be applied to other species – in particular, dogs.”

The study is published in the journal Forensic Science.