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Australia uses new DNA tool to unravel missing persons mysteries

MELBOURNE, Australia – When a man washed up on the shores of Christmas Island in 1942, lifeless and bent over in a raft riddled with shrapnel, no one knew who he was.

It was not until the 1990s that the Royal Australian Navy began to suspect that he might be a sailor from HMAS Sydney II, an Australian warship whose crew of 645 went missing at sea when she sank off the coast of Western Australia during World War II. Second war.

In 2006, the man’s remains were exhumed, but DNA extracted from his teeth yielded no match to a list of people Navy officials believed to be his descendants. With few leads, the scientist who performed the DNA test, Jeremy Austin, told the Navy about an emerging technique that could predict a person’s ancestry and physical traits from genetic material.

The method, known as DNA phenotyping, relies on variations in the genome combined with traits related to physical appearance to assess the likelihood of a person having a certain hair, eye or skin color. skin, among other characteristics. It differs from older techniques in that it does not require the DNA to be matched to an existing sample in a database.

The new tool is primarily used by police departments around the world to help identify suspects in cases where there are no witnesses. This raised concerns about the potential for racial profiling.

In Australia, forensic scientists are repurposing the technique to help link missing people to unidentified remains in hopes of solving long-standing mysteries. In the sailor’s case, Dr Austin sent the sample to researchers in Europe, who reported that the man was of European ancestry and most likely had red hair and blue eyes.

Credit…Australian War Memorial

This alone was not sufficient to identify the sailor, but it narrowed the search. “In a ship full of 645 white men, you wouldn’t expect to see more than two or three with this pigmentation,” said Dr Austin, deputy director of the Australian Center for Ancient DNA at the University of Australia. Adelaide.

In Australia, there are thousands of long-term unsolved missing persons cases, as well as hundreds of unidentified remains held by police across the country. The Australian Federal Police National DNA Program for Unidentified and Missing Persons, launched in July 2020, applies a range of techniques to help law enforcement find potential links between remains and missing persons, including DNA phenotyping.

This medico-legal tool, which has been progressing slowly since the mid-2000s, is similar to genetic tests used to estimate the risks of certain diseases. About five years ago, scientists from the Australian Federal Police began developing their own version of the technology, which combines genomics, big data and machine learning. It became available for use last year.

DNA phenotyping predictions – whether a person had, say, brown hair and blue eyes – will be brought to life by a forensic artist, combining the phenotype information with renderings of the bone structure to generate a reconstruction three-dimensional digital facial.

“It’s an investigative lead we’ve never had before,” said Jodie Ward, director of the new program.

His lab, located in the capital Canberra, will begin offering this service to police departments across the country later this year. For now, she and her team are refining the technique by testing it on DNA samples taken from the remains of people who donated their bodies to science. Soon, the technology could also include predictions for age, body mass index and height, as well as certain facial characteristics like lip fullness and cheek structure.

Although Dr Ward is focusing on missing persons cases, DNA phenotyping technology will also be used by the Australian Federal Police to aid in criminal investigations.

In the United States, police departments have for years used private DNA phenotyping services, such as that of Virginia-based Parabon NanoLabs, to try to generate facial images of suspects. Images are sometimes distributed to the public to facilitate investigations.

Many scientists, however, are skeptical of this application of the technology. “You can’t do a full facial prediction right now,” said Susan Walsh, a biology professor at Indiana University-Purdue University in Indianapolis, who developed some of the first phenotyping methods for color. eyes and hair. “The basis of genetics is absolutely not there.”

The prediction of facial images has been condemned by human rights organisations, including the ACLU, who suggest it risks being skewed by existing social biases.

One such episode took place in Germany in 2007, when DNA phenotyping predicted that a sample taken from a crime scene involving the murder of a police officer belonged to a woman of Eastern European ancestry. The same DNA was later linked to dozens of serious crimes across Western Europe, prompting a theory that the perpetrator was a serial offender from an itinerant Roma community.

The recurring genetic material turned out to belong to a Polish worker who had accidentally contaminated the cotton swabs used to collect the samples.

Similar concerns have been raised about DNA phenotyping in Australia, where certain populations – particularly Indigenous Australians – are arrested and imprisoned at disproportionately high rates.

Gabrielle Samuel, a sociologist at King’s College London, said DNA phenotyping “will ultimately reflect the biases of the climate in which it is used”.

But Dr Ward, director of the Australian Federal Police’s new program, said using DNA phenotyping on unidentified remains did not raise the same ethical issues because the people died and because the cases involve people missing, not crimes.

“Families want all techniques applied to these cases if it helps answer the question of what happened,” she said.

Dr Ward said she does not see DNA phenotyping as a silver bullet to solving long-term missing persons cases. She and her team will also use more traditional methods, such as skeletal analysis, research of dental records and radiocarbon dating. “A forensic technique will not give us the essential information,” she said.

Such was the case of the mysterious sailor. After his genotype was sequenced and his phenotype predicted, a team of scientists from several Australian institutions, including Dr. Ward’s program, used this information to track down a woman they believed to be a living relative of the soldier. They checked his DNA and found a match.

His name was Thomas Welsby Clark, son of wealthy sheep farmers and descendant of Scottish immigrants. He had been a sailor on the ill-fated battleship and most likely escaped the burning ship in a raft before dying at sea. A photograph of Mr. Clark was found and Navy technicians colorized it. They gave her bright blue eyes and red hair.


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