- The statically charged hair of domestic cats easily gets stuck on the owner’s clothing
A new DNA testing method could soon catch criminals if they are cat owners.
Around a quarter of British households own a cat, and their pets’ static-charged hair easily gets caught on the owner’s clothing.
This means that a criminal cat owner could theoretically be brought to the crime scene using cat hair brushed from their clothing.
But cat hair isn’t as good as the criminal’s own DNA, which contains telltale repeating sections of genetic code called “short tandem repeats” (STRs) that are found in a type of DNA called nuclear DNA.
There is not enough nuclear DNA to detect these STRs in cat hair because the cat’s hair root, which contains this type of DNA, is usually dried out.
Around a quarter of British households own a cat, and their pets’ static-charged hair easily gets caught on the owner’s clothes (file image)
However, cat hair is a better source of a type of DNA called mitochondrial DNA, which is passed down by women.
However, this is usually broken down into fragments in the hair, resulting in an incomplete DNA measurement.
Because domestic cats all have the same small number of ancestors, a typical sample could include thousands of different cats.
However, scientists have now made a breakthrough that could revolutionize cold cases like unsolved murders by matching cat hair to a specific cat.
Researchers can now take fragments of mitochondrial DNA and make billions of them using a PCR test similar to those used for Covid.
The fragments each represent the same genetic code from the cat’s mitochondrial DNA – but each is like an incomplete photocopy.
But if these are multiplied billions of times, a technology that might struggle with just a few copies can identify the genetic code that the fragments share.
This restores the cat’s complete mitochondrial DNA – something that was never possible before.
A criminal cat owner could theoretically be brought to the crime scene using cat hair brushed from his clothing (file image)
It has been shown to work to identify the remains of a lost cat using DNA from its hair verified against the cat’s son.
Dr. Jon Wetton from the University of Leicester, a member of the team behind the breakthrough, said: “Cat hair at crime scenes has previously been ignored because cats have such similar DNA.”
“But this method can identify individual cats decades after their death and could therefore be invaluable in cold cases.”
“In a previous murder case, we used the previous technique, but were lucky that the suspect’s cat had an unusual mitochondrial variant, as most cat lineages could not be distinguished from each other.”
“But with our new approach, virtually every cat has a rare DNA type and therefore the test will almost certainly be conclusive if hairs are found.”
The research was published in the journal Forensic Science International: Genetics.
The new technique is said to be about ten times more sophisticated than a previously used technique that examined only a short fragment of cat hair DNA.
Professor Mark Jobling, co-author of the study from the University of Leicester, said: “In criminal cases where human DNA is not available for testing, animal hair is a valuable source of linking evidence and our method makes it that much better.” powerful.
“The same approach could be applied to other species – especially dogs.”