Criminals who own cats may soon find themselves caught by a groundbreaking DNA testing method that utilizes cat hairs. Around a quarter of households in the UK own cats, and the statically charged hairs of these pets easily cling to their owners' clothes. This means that if a cat-owning criminal was present at a crime scene, their cat hairs, which have been brushed off their clothing, could potentially place them at the scene.
While cat hairs are not as effective as the criminal's own DNA, which contains distinct repeated stretches of genetic code, known as 'short tandem repeats' (STRs), they do contain mitochondrial DNA passed down through the female lineage. However, mitochondrial DNA found within cat hairs is typically fragmented, making it challenging to obtain a complete DNA reading. Additionally, since pet cats share a small number of common ancestors, a typical cat hair sample could belong to thousands of different cats, making identification difficult.
Now, scientists have made a breakthrough that could revolutionize cold cases, such as unsolved murders, by matching cat hairs to a specific cat. Using a PCR test similar to those used for Covid, researchers can multiply fragments of mitochondrial DNA billions of times. These fragments each reveal the same genetic code from the cat's mitochondrial DNA, albeit as incomplete photocopies. However, when the billions of fragments are analyzed collectively, technology can identify the common genetic code they share, thereby recreating the cat's full mitochondrial DNA.
This groundbreaking technique was successfully tested in identifying the remains of a lost cat, using DNA from its hair that was verified through the cat's son. Dr. Jon Wetton, a member of the research team from the University of Leicester, explained that until now, cat hair found at crime scenes was overlooked due to the similarity of cats' DNA. However, this new method can differentiate between individual cat profiles, even decades after their death, making it invaluable in cold cases.
The technique has been found to be approximately ten times more precise than a previously used method that examined only a short fragment of cat hair DNA. Professor Mark Jobling, a co-author of the study, emphasized that in criminal cases where human DNA is unavailable for testing, pet hair becomes a valuable source of linking evidence. He also suggested that this approach could be applied to other animals, such as dogs.
The findings of this research have been published in the journal Forensic Science International: Genetics. With this new approach, the identification of criminals through cat hairs could significantly aid in solving cold cases and provide crucial evidence, where previously none existed. As technology continues to advance, the potential for utilizing DNA from pet hair in criminal investigations may extend to other species as well.