From tracking criminals to sniffing out drugs, dogs have long helped police crack cases.
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police → track → cases
Now experts are hoping a database of canine DNA could offer vital leads.
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database → hop → leads
While hair, saliva and other canine material may be found at crime scenes, or on individuals connected to incidents, scientists say they are often not fully investigated.
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they → find → incidents
Yet such traces could provide valuable clues, from the identity of a canine perpetrator to evidence a dog’s owner was present at a crime scene.
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owner → provide → scene
“You might have a human case, kidnapping, for example,” said Prof Denise Syndercombe Court, a forensics expert at King’s College London who is leading the work.
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who → have → work
“Lots of us have dogs.
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Lots → have → dogs
We live with dogs all the time.
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We → live → dogs
And so if you can identify canine material associated with a crime like that, then that can be very powerful in being able to provide intelligence to help solve a human case where there’s no other evidence.
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that → identify → case
As a result, researchers at King’s College London and the Royal Veterinary College have teamed up to harness the potential of canine DNA.
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researchers → team → DNA
“Forensically, we don’t have loads of DNA,” said Syndercombe Court.
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Court → have → DNA
“You have a few cells that are left at a crime scene …
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that → have → scene
So you’ve got to make something useful out of that.”
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you → get → that
One approach is similar to that employed in the forensic analysis of human DNA, which is to focus on very small segments called short tandem repeats (STRs).
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which → employ → segments
This technique involves looking at the number of times these small segments are repeated in the DNA, resulting in two numbers for each STR – one inherited from each parent.
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segments → involve → parent
Syndercombe Court noted the set of numbers provided a virtually unique profile – be it for a human or a dog.
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it → note → human
By focusing on STRs the team has built a database covering 80 different breeds – the first of its kind in the UK.
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team → focus → UK
For the 10 most common breeds, including labradors, cocker spaniels and miniature schnauzers, samples were taken from at least 50 dogs of each breed.
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samples → include → breed
The upshot is that canine DNA from a crime scene can be analysed and the results either compared with those from a particular dog – allowing that animal to be confirmed or ruled out as being linked to a crime – or screened against the database, potentially allowing experts to identify the breed of dog from which it came.
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it → analyse → which
The latter could be particularly useful where the dog thought to be linked to a crime is unknown, or where samples cannot be taken from a canine suspect, or where the sample does not match the DNA of a dog under suspicion.
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sample → think → suspicion
Syndercombe Court said her team now hoped to expand their database to include breeds such as pitbull terriers, American XL bullies and Japanese tosas that are banned in the UK.
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that → say → UK
While the STR analysis focuses on DNA from the nucleus of a cell, the team have also created a database using another approach: sequencing DNA from within mitochondria – the tiny structures that power cells.
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that → focus → cells
With many mitochondria per cell, this approach can be useful where there is very little material to work with – although it is more limited as this DNA is only passed from mother to offspring.
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DNA → be → offspring
The focus on doggy DNA has already offered insights for police investigations.
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focus → offer → investigations
In one case, the approach shed light on whether serious injuries sustained by a man were down to another person – as he claimed – or occurred when he tripped over his own dogs as they attacked the accused.
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they → shed → accused
Forensic analysis supported the latter.
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analysis → support → latter
“We looked at the T-shirt [of the accused] and there were holes in the T-shirt,” Syndercombe Court said, adding the team also found DNA from two different dogs on the garment.
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team → look → garment
In another case, the DNA analysis shed light on a sheep attack.
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analysis → shed → attack
“We got some decent DNA from the crime scene, and the police thought it was a particular person’s dogs,” said Syndercombe Court.
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Court → get → scene
However the DNA from those dogs did not match the DNA recovered from the crime scene.
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DNA → match → scene
“So we were not only able to exclude his dogs, which were of a particular breed, but also say the breed of dog that [did] this attack was very likely to be [another breed],” said Syndercombe Court.
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Court → exclude → attack
Dr Nicholas Dawnay, an expert in forensics at Liverpool John Moores University – who was not involved in the work – said research assessing how best to use canine DNA collected from crime scenes was hugely important.
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research → involve → scenes
“Whether it is a dog attacking a human or livestock or wildlife species, the ability to match the individual dog back to the attack is the primary goal.
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ability → attack → attack
Obtaining breed information at the early stages of an investigation may help narrow down the pool of possible dogs, which is exciting,” he said.
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he → obtain → dogs
But Dawnay said a big challenge remained regarding the funding of canine forensic casework: “Police budgets are stretched and without effective funding, the benefits of this research may struggle to be realised.”
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benefits → say → research
The Aporia
