DNA analysis
July 11, 2010
On July 11, 1995, Bosnia experienced the largest widespread killings and other war crimes in Europe since World War II.
United Nations authorities say that in a span of just a few days, Serb separatists killed about 8,500 Bosniaks and buried their bodies in mass graves near Srebrenica. However, today, many victims of the war crimes have still not been identified.
Since 2006, the International Committee on Missing Persons (ICMP) has used DNA analysis to link bone fragments and other organic material buried in Bosnia's mass graves with the DNA of potential relatives who have donated their genetic material to be matched up with the victims.
Qiagen, a German company based in Hilden outside Dusseldorf in western Germany, has developed the technology used for much of the biological and genetic testing.
"There are quite a number of difficulties, especially in the extraction of older bones, which have been buried in the ground for years under very adverse conditions," said scientist Mario Scherer, who works on samples from Bosnia.
"The quality of the genetic material in these bones is impaired by chemical and physical agents and processes through decomposition by bacteria very strongly," he added. "The aim is to extract the genetic material as cleanly as possible."
Scherer works mostly with his centrifuge, a blue, futuristic-looking cube just larger than a microwave oven. It sits on Scherer's laboratory bench and he puts his samples inside, where the biological material can be separated after being spun around at high speed.
The genetic material is cleaned with so-called pillars, or plastic tubes filled with a material that binds to the genetic molecules and separates them from interfering substances.
Special precautions
Initially, Qiagen's scientists thought that their centrifuge would mainly be used to analyze simple DNA sources, such as blood samples.
But it soon became clear that the blue cube could also read more problematic samples of genetic molecules, even from bones that have been buried for many years.
Other scientists working in this field agree that special precautions must be taken even from the moment of extraction from the field.
"We also must make sure that no additional external contamination is acquired during the process," said Thomas Parsons, the director of forensic science at the International Commission on Missing Persons, in a 2006 interview on Qiagen's website.
"The small amounts of DNA that we are working with can reach the levels of PCR (detection of polymerase chain reaction) technology, so it is easy to pick up any exogenous contamination that may be present," he added.
DNA identification is crucial
Parsons' colleagues from ICMP use Qiagen's techniques to extract genetic molecules from bones that have been buried for 15 years.
"DNA is really the only mode for identification," said Rene Huel, the head of the IPMC laboratory in Sarajevo. "Other, more traditional ways of identification could not be applied here in this region."
After the war in Bosnia, many thousands of people are still unaccounted for. Many bones discovered in mass graves could not initially be identified. There are hundreds of bags of bones in cold storage, which are still waiting to be examined.
Huel added that their job is that much harder because the perpetrators have done everything to conceal the extent of war crimes.
"You do not have one individual in one grave site," he said. "You may have one individual in four or five grave sites. We try to bring back as much of the body as possible. To bring back the missing person to the family is one of the big challenges we face."
Scientists are able to find DNA fragments from the pieces of bone buried around Bosnia. Then, they can compare that with the results of DNA from possible relatives in the region who have agreed to provide blood samples.
Since work began, the ICMP has been able to describe the fate of more than 15,000 missing people. During the past 12 months alone, 775 more victims have been identified. The scientists have informed their living relatives so that they can be buried on the anniversary of the Srebrenica massacre.
"Hopefully we will have an impact on a greater world," Huel said. "People will realize that these crimes or what they are committing hidden will not be hidden. This type of DNA technology can tell the truth about what has happened."
Author: Michael Lange / Cyrus Farivar
Editor: Kate Bowen