Researchers from the University of Leicester have unveiled an unconventional tool in forensic investigations: cat hair. They have shown that a single cat hair contains DNA that could link a suspect, a crime scene, or a victim.
With approximately 26 percent of UK households playing host to a feline companion and the average cat shedding thousands of hairs annually, it appears our furry friends may unwittingly aid in solving crimes.
A woman lines up waiting for her cat to be blessed by Father Walbert in the Marolles neighborhood in Brussels, on October 1, 2023. The blessing of the animals perpetuates the tradition of Saint Francis of Assisi from year to year.
Cat Caught Your Criminal?
While human culprits may be cautious about leaving behind their own DNA, transferred cat hair carries its own genetic code, potentially serving as a link between a suspect, a crime scene, or even a victim.
The researchers introduced a highly sensitive method capable of extracting extensive DNA data from a single cat hair. Lead author of the study, Emily Patterson, a PhD student at Leicester, explained that "hair shed by your cat lacks the hair root, so it contains very little useable DNA."
"In practice we can only analyse mitochondrial DNA, which is passed from mothers to their offspring, and is shared among maternally related cats," Patterson noted.
This implies that DNA extracted from hair alone cannot definitively distinguish one cat from another, highlighting the need to extract as much information as possible from forensic analyses.
Nonetheless, the research team devised a novel method to decode the complete sequence of mitochondrial DNA. This technological leap boasts an approximately tenfold increase in precision compared to the earlier method, which focused on a limited DNA fragment.
Dr. Jon Wetton, co-leading the study from the University's Department of Genetics and Genome Biology, recalled a previous murder case where they applied the earlier technique.
They were fortunate that the suspect's cat possessed an uncommon mitochondrial variant, as distinguishing between most cat lineages proved challenging.
However, their new approach ensures that nearly every cat possesses a rare DNA type, greatly enhancing the informativeness of the test when hairs are discovered.
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How to Cat-ch a Suspect
To validate their method, the team conducted a test in a case involving a lost cat. They successfully matched DNA from the skeletal remains of a missing female cat with DNA obtained from hair found on her surviving male offspring.
Mark Jobling, a Professor of Genetics and co-lead of the study, emphasized that in criminal cases where human DNA is unavailable for testing, pet hair emerges as a valuable source of linking evidence.
Their method significantly amplifies its potency. Furthermore, this same approach could be extended to other species, such as dogs.
"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. The same approach could also be applied to other species - in particular, dogs," Jobling said in a statement.
The team's findings were published in the journal Forensic Science International: Genetics.
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