Medical examiner taps DNA science to find missing persons

February 18, 2018 by Verena Dobnik

For families who have searched years for missing loved ones, donating a sample of their DNA is often a last, desperate act to confirm their worst fears.

New York City's medical examiner is leading a nationwide effort to collect and match it with unidentified human remains. It's a way to finally give family members some answers and maybe some solace.

"People will not rest without answers, at least some answers," said Dr. Barbara Sampson, the city's chief medical examiner.

Over the last decade, thousands of DNA samples have been donated to the city's medical examiner's office. Most include swabs of saliva from close relatives, but also DNA taken from items used by the missing persons themselves, including toothbrushes, combs, razor blades and, once, even a sanitary napkin.

They've led to the identification of about 50 missing people each year, all of whom had been found dead. But for many who have submitted samples, the wait continues.

"Part of you hopes they never call you, because if they call, that means it's over," said Rose Cobo, who submitted DNA to the program after her adult niece vanished in 2016 after being treated at a Brooklyn hospital for postpartum depression following the birth of a son. Chelsea Cobo's whereabouts are still unknown.

The program helped end Luis Merchan's quest to find his younger brother, Manuel, who was reported missing in 2015 after he left his native Ecuador and crossed the U.S. border from Mexico. DNA matched with the remains of a 35-year-old "John Doe" who succumbed to exposure and dehydration in the Texas desert.

"It's sad," Merchan said. "We hoped Manuel would call one day. But we at least know what happened."

On any given day, there are as many as 100,000 active missing-persons cases in the U.S., according to the FBI's National Crime Information Center. Most of those people are eventually found safe. The medical examiner's office program is open to people whose loved ones have been missing 60 days or more.

The New York City medical examiner's office has been a pioneer in advanced DNA techniques since 9/11, when it was tasked with using genetic evidence to identify and sort tens of thousands of small pieces of human remains found in the rubble of the World Trade Center.

One such advance, Sampson said, was learning how to get good genetic material out of bone fragments. DNA testing once required a large sample of blood or saliva that was often destroyed in the process. The latest genetic technology allows a few cells to be reproduced for DNA that lasts indefinitely.

Pulverized genetic material is spun in a centrifuge and turned into a clear liquid that's poured into test tubes on a robotic assembly line. The tubes are bar-coded and padlocked in metal cages in a secure vault.

Genetic profiles developed from the tests are plugged into the databank called the National Missing and Unidentified Persons System. The system is capable of searching for unique similarities in DNA strings that indicate two people are related.

"Our job is to help identify your loved one and return them to you, no matter where in the United States. They don't have to have died here in New York City," says Mark Desire, assistant director of the medical examiner's Department of Forensic Biology.

Mary Lyall submitted her DNA to the New York City medical examiner, along with her husband's, as part of her hunt for her missing daughter.

Suzy Lyall was 19 when she disappeared in 1998. She was last seen on the University at Albany campus getting off a bus.

After she vanished, her mother sifted through her room at home looking for clues. In a wastebasket, she found a sanitary napkin Suzy had wrapped and discarded amid crumpled paper.

Two decades later, no match has been made.

"I still look out the window and think, 'Where is she?'" Lyall said.

Explore further: Scientists still working to identify 9/11 victims (Update)

More information: Office of the Chief Medical Examiner: nyc.gov/ocme

Related Stories

Scientists still working to identify 9/11 victims (Update)

May 9, 2014
Thousands of vacuum-sealed plastic pouches filled with bits of bone rest in a Manhattan laboratory. These are the last unidentified fragments of the people who died in the World Trade Center on Sept. 11, 2001.

Recommended for you

Genetic determinants of telomere length in African American youth

September 25, 2018
Telomeres are DNA-protein structures that play a vital role in maintaining DNA stability and integrity. Telomere length (TL) is an important biomarker of aging and overall health, but TL has been mostly studied in adult populations ...

Thousands of unknown DNA changes in the developing brain revealed by machine learning

September 24, 2018
Unlike most cells in the rest of our body, the DNA (the genome) in each of our brain cells is not the same: it varies from cell to cell, caused by somatic changes. This could explain many mysteries—from the cause of Alzheimer's ...

Mitochondrial diseases could be treated with gene therapy, study suggests

September 24, 2018
Researchers have developed a genome editing tool for the potential treatment of mitochondrial diseases: serious and often fatal conditions which affect 1 in 5,000 people.

How to edit your mitochondria

September 24, 2018
Mitochondrial genetic engineering is the adaptation of genetic engineering techniques to specific mitochondrial problems. Although it is not common to be born with severe mitochondrial issues, we will all eventually have ...

Height may be risk factor for varicose veins, study finds

September 24, 2018
The taller you are, the more likely you are to develop varicose veins, according to a study led by Stanford University School of Medicine researchers that examined the genes of more than 400,000 people in search of clues ...

Researchers identify new genetic disorder

September 21, 2018
Researchers from Michigan State University College of Human Medicine and physicians from Spectrum Health have identified for the first time in a human patient a genetic disorder only previously described in animal models.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.