New DNA analysis tool can help forensic experts fight crime

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Australian scientists have developed a novel test which can reveal the amount of DNA people shed, an advance that would help forensic examiners catch criminals.

The test, using a DNA staining dye, can help forensic examiners at crime scenes determine the last person who made contact with an item.

"We know that some people pass on more of their DNA because when they touch something more of their cells are left behind," said Adrian Linacre, Professor and Chair of Forensic DNA Technology at Flinders University, Australia.

"They are called shedders but it's very difficult at the moment to see who is a shedder," he added.

The shedder status of a specific person of interest may be relevant in determining the likelihood of whether a major contributor in a mixed DNA profile was the last person to make contact with an item and is therefore linked to a crime.

The use of a DNA staining dye can visualise the presence of cellular material and allow real-time collection of the cellular material to a swab head.

The results are published in the journal Forensic Science International: Genetics.

Currently, the forensic examiners are working blind because they can't see the exact location which contains deposits of DNA and therefore have to sample where they think DNA might be stored.

"What we have developed is a simple test which can work out if an individual is a shedder in a matter of minutes. It tells us who has the better chance of passing on DNA," Linacre said.

"The shedders test also showed men shed more than women do, and that thumbs leave the most accurate traces," the researchers said.

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