Tests Planned For The Unknown
Associated Press, May 12, 1998
(AP) -- Scientists will compile a physical profile and use a cutting-edge
form of DNA testing in an attempt to identify the Vietnam veteran buried
in the Tomb of the Unknowns at Arlington National Cemetery.
The remains, originally entombed 14 years ago, will be exhumed Thursday for examination by military scientists to determine whether they are those of Air Force 1st Lt. Michael J. Blassie, as his family believes; another serviceman who crashed in the same area as Blassie; or those of a truly anonymous Vietnam veteran.
After analyzing the bones' DNA -- the substance that carries a person's hereditary code -- and attempting to determine the weight, height and other physical characteristics of the remains, scientists will compare the results with samples from members of nine families.
``We don't know exactly what we will find,'' said Robert W. Mann, one of the anthropologists heading the investigation. ``All we really know is that there are six bones.'' Records of the initial testing on the remains are not available, and even if they were, researchers would not want them. ``We want to look at this with no preset ideas'' about the identity of the soldier, Mann said.
Testing will be done by the Armed Forces DNA Identification Laboratory and the Armed Forces Institute of Pathology.
Because of the age and condition of the bone samples, researchers will examine the mitochondrial DNA, or mtDNA, rather than the traditional nuclear DNA. Nuclear DNA is found in the nucleus of the cell, and will not withstand great environmental changes -- significantly variable temperatures, rainfall, soil acidity -- such as are found in Southeast Asia.
Although mtDNA is much more plentiful -- thousands in a single cell -- it is not as reliable as nuclear DNA for identification purposes.
MtDNA testing is a new form of genetic analysis. Originally used in 1991, it has been utilized by the Defense Department to identify 93 other previously unidentified military personnel, who died as far back as the Civil War. Traditional DNA testing would have been difficult, if not impossible, in many of those cases.
When combined with the anthropological analysis, mtDNA analysis should draw an accurate picture of the currently unidentified soldier.
The remains, interred in 1984, were initially examined without the aid of DNA testing. Technological advancements have made identification of human remains far more reliable than previously. ``We will start over with all new technology,'' Mann said. ``We will start at square one to determine the identity.''
The mtDNA tests are done by breaking down the bone sample and analyzing the genetic code. The mtDNA is then compared with that of a maternal relative; unlike nuclear DNA, mtDNA is passed down only through the mother.
Even with a positive mtDNA match, the identity cannot be absolutely determined. MtDNA is not unique to every individual.
``One out of every 1,000 people have the same mtDNA sequence,'' said Dr. Mitchell H. Holland, head of the DNA testing team. Through the anthropological profile, and narrowing the field of possible victims, mtDNA becomes a very effective means of identification. ``We look at the totality of evidence, not just one piece,'' Mann added.
Holland expects mtDNA tests and the anthropological profile will be effective in differentiating among the nine possible victims.
The mtDNA testing should take about 20 working days, according to Holland.