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Male lineage helps identify missing service members

Male lineage helps identify missing service members

Lena Gunn (left), Armed Forces Medical Examiner System's Armed Forces DNA Identifical Laboratory DNA analyst, swabs the cheek of Damien Rispoli, nephew of missing Army Air Force Sgt Vincent J. Rispoli, 703rd Bomb Squadron, 445th Bomb Group (Heavy) waist gunner, during a Defense POW/MIA Accounting Agency Family Member Update in Philedelphia, Pa., Sept. 8, 2018. DNA analysts from AFMES-AFDIL were on site to collect DNA samples from family members using what’s called a buccal swab, which looks similar to a cotton swab to to test for mitochondrial DNA, Y-DNA and autosomal DNA. (U.S. Air Force photo by Staff Sgt. Nicole Leidholm)

Male lineage helps identify missing service members

Dr. Timothy McMahon, Armed Forces Medical Examienr System Department of Defense DNA Operations director (middle), speaks with Greg Gardner, U.S. Army Casualty and Mortuary Affaris Operations Division (CMAOD), Past Conflict Repatriations Branc (PCRB) cheif, and Denise Hazlewood, grand neice to missing Army Privet First Class Paul Carlton Gunter, Company A, 81st Armored Reconnaissance Battalion, during a Defense POW/MIA Accounting Agency Family Member Update in Philadelphia, Pa., Sept. 8, 2018. The DPAA conducts periodic and annual government briefings for families of service members who are missing in action. These events are designed to keep family members informed of those still missing and to discuss in detail the latest information available about their specific case. Nearly 400 families came out to this months’ FMU. (U.S. Air Force photo by Staff Sgt. Nicole Leidhom)

DOVER AIR FORCE BASE, Del. – The Armed Forces Medical Examiner System’s Armed Forces DNA Identification Laboratory briefed families of missing service members at the Defense POW/MIA Accounting Agency’s latest family member update in Philadelphia, Pennsylvania, September 8, 2018.

The DPAA conducts periodic and annual government briefings for families of service members who are missing in action. These events are designed to keep family members informed of those still missing and to discuss in detail the latest information available about their specific case. Nearly 400 families participated in this months’ FMU making it the most attended FMU since Dallas, Texas, 2012.

DNA analysts from AFMES-AFDIL were on site to collect DNA samples from family members using a buccal swab, which looks similar to a cotton swab.

The swabs are used to test for mitochondrial DNA and nuclear DNA. Both of these types of DNA can be utilized for human identification and forensic testing.

Of those, mtDNA is not unique to an individual, but is common to an individual’s maternal lineage. Nuclear DNA, where Y- Chromosomal DNA and auDNA are found, is unique to an individual, with half of the DNA coming from the mother and half coming from the father.

Y-Chromosomal DNA is passed from father to son thru the paternal lineage with brothers sharing the same Y-Chromosomal DNA and the Y-Chromosomal DNA will be passed down to their sons. However, sisters will not have the Y-Chromosomal DNA and their son’s would have Y-Chromosomal DNA passed from their son’s father.

“There is only one Y chromosome per cell, compared to 100’s of mitochondria,” said Julie Demarest, AFMES-AFDIL Family Reference Sample technical leader. “However, in cases where a service member does not have any living or available mtDNA references, Y-[Chromosome Short Tandem Repeat markers] testing can provide another avenue for identification, and our technology has improved to the point that more and more often we are able to obtain Y-STR information for an unknown sample.”

In 2006, AFMES-AFDIL was able to test for auSTR and Y-STR, with the first case being utilized in the DPAA mission to identify a service member missing from the Vietnam War, according to Dr. Timothy McMahon, Department of Defense DNA Operations director. However, it wasn’t routinely used until 2010 when AFMES-AFDIL had an increase in family references.

By 2013, AFMES-AFDIL added a Low Copy Number Y-STR amplification method along with an enhanced DNA purification method.

“This doubled our success rates to 50 percent or greater,” said McMahon. “Additional processing efficiencies allowed for us to maintain a 60 percent success rate for Y-STR and auSTR in 2018.”

This has allowed AFMES-AFDIL to increase the likelihood of identifications of individuals sharing a more common mtDNA sequence or in instances where there are no maternal references. The ability to use any male relative along the service member’s paternal line, increases the likelihood of finding a suitable family reference to have on file. 

“Without those family references, that sequence I get from the bone is just a sequence if I don’t have anything to compare it to,” said McMahon. “They are our greatest resources in identifying missing service members.”

McMahon said exclusions are just as important because they can rule-out individuals who may have similar mtDNA but unique Y-STRs.

“It’s great when we make a connection to a single service member,” said McMahon. “It gives us the best chance to find out who the service member truly is.”