DNA breakthrough could help solve thousands of cold cases

Interpol scientists developed a new DNA profiling method using three genetic markers from degraded evidence. Photo / 123rf

Thousands of cold cases could be solved after a breakthrough in DNA profiling.

Forensic scientists from Interpol have developed a new method for identifying victims and suspects from previously unusable, decades-old evidence.

Heavily degraded samples of blood, bones or semen from crime scenes and missing-persons investigations could now yield crucial DNA information.

For the past 30 years, forensic scientists have relied on matching a minimum of six common genetic markers – an identifiable DNA sequence on a chromosome – from one sample to another.

However, this meant that police were forced to discount vital DNA evidence because it was too damaged, such as bones that had remained in seawater for years or outdoor bloodstains degraded by UV exposure.

Three markers

Now, scientists can match DNA with only three markers, meaning they need less DNA evidence for official identification.

Scientists identify an individual by using a mathematical algorithm that matches these rare genetic markers with those in other DNA samples.

Police can quickly narrow a list of 100 potential suspects to a handful because they can discount false matches from common genetic markers.

This means that investigations that were closed because of a lack of suspects or evidence could be reopened and murder victims could finally be identified after decades of uncertainty.

Detectives might also find their workload substantially reduced and cases solved more quickly as they would not waste time following up false leads thrown up by irrelevant matches.

It is one of the biggest advances in DNA profiling in decades and has already yielded new lines of investigation in unsolved cases, The Telegraph has been told.

Interpol believes the method will be adopted by police forces globally, including Scotland Yard, in the years ahead.

‘Enormous possibility’

A team of three forensic scientists from Interpol’s DNA unit developed the algorithm alongside two researchers from Smart Research BV, a mathematical software company in the Netherlands.

The team used the details of more than 183,000 individuals to substantiate their findings, which have been published in the journal Genes.

Dr François‑Xavier Laurent, a DNA database manager at Interpol and a co-author of the study, said: “We have been running this method on the data that we currently have, for research and development purposes.

“We are starting to see interesting investigation leads that we are hoping to provide to the countries in a very short time. You need to wait for one breakthrough that will help countries to really adopt this method.

“We are not at this stage yet, but hopefully, within the next few months or years, we will be able to have a catalogue of investigations that were helped with this new method and then its adoption will follow, I’m sure.

“The possibility is enormous. We just need a bit of time to have this method adopted.”

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