WASHINGTON – Hundreds of researchers at two military laboratories analyze bone fragments to give closure to the families of missing U.S. service members,some who have waited decades to learn their loved ones' fate.
To identify the missing troops from as far back as the Civil War,forensic anthropologists use methods ranging from DNA to comparing bones to X-rays,said James Canik,deputy director of the Air Force DNA Identification Laboratory in Rockville, Md.
“What you see on those crime scene shows is pretty accurate,” he said. “It's a very complicated thing,and it takes a lot of people to make the process work.”
Different types of DNA have to be used for comparisons,Canik said. Each person has his or her own unique nuclear DNA,but Canik said it can be compared to that of siblings' to find similarities. More specific types such as Y-DNA,which is paternally inherited,and mitochondrial DNA,which is maternally inherited,can also be used,he said.
“If we can tell who it's not,that helps to eliminate a whole lot of possibilities,” Canik said.
About 12,000 family members related to 7,600 service members missing from the Civil War through the Cold War have given DNA samples. But the researchers are far short of 100-percent family participation,said Tom Holland,scientific director for the Joint POW-MIA Accounting Command.
Starting with the first Gulf War,the military has taken a DNA sample from every soldier,sailor,Marine and airman heading overseas to make identification easier.
Without samples from all family members to match all of the remains,Holland said it can be difficult to definitively match the DNA.
Even if family members do not want to find the remains of their missing relative,their reference samples can help researchers by eliminating other options in different cases,said Alexander Christensen,DNA coordinator with the Central Identification Laboratory at Hickam Air Force Base in Honolulu, Hawaii.
“By providing a reference,they are helping us to identify other remains through exclusion,” Christensen said. “Those other casualties may be relatives of people to whom it is really important to get back the remains.”
Christensen said mitochondrial DNA is the most reliable because it can be compared to that of other relatives and does not deteriorate as quickly as nuclear or Y-DNA.
In a few cases,he said they extracted nuclear DNA from items such as hearing aids and watches. DNA from old stamps has resulted in two identifications that Holland could recall,although it is not always a sure thing,he said.
“Even if you get a good DNA sequence out of it,you still can't be sure who licked the stamp,” Christensen said. But DNA cannot always be used,Canik said. Some remains were stored in formaldehyde,which destroys the DNA,he said.
A new process known as demineralization can help to undo some of the damage to find the DNA,he said.
“We know that there's DNA in these samples,but our problem is undoing the cross-linking without destroying the DNA in the process,” Canik said.
In addition to identifying missing service members with DNA,the researchers from the military labs have also helped with identifications in New Orleans after Hurricane Katrina and in Southeast Asia after the 2004 tsunami.
Holland said they can also compare bones to chest X-rays and dental records. And researchers can align photographs of missing soldiers to recovered skulls to see if there is a match,he said.
But it is not the best solution,he said.
“Is this going to resolve hundreds? No,” Holland said. “This is a stop-gap measure until we can break the code on the DNA.”