However, this is far from the first time that the genetic material of family members has been used to give names to unknown remains. Scientists around the world have used DNA to identify missing persons and victims of war, genocide and natural disasters. The International Commission on Missing Persons, or ICMP, a Netherlands-based non-governmental organization, has conducted several DNA profiling efforts, including in the western Balkans, to identify Muslim men and boys killed during the 1995 Srebrenica genocide during the Bosnian War . In these cases, researchers typically invite close family members of the missing person to provide blood samples; then they create DNA profiles from the samples to compare them to those obtained from remains.
The organization’s testing methodology focuses on a type of DNA variation called short tandem repeats, or STRs. In contrast, consumer testing analyzes people’s genetic code by examining single nucleotide polymorphisms, or SNPs, single-letter changes in DNA sequences that make people unique. STRs are useful for determining closer relationships, while SNPs are more stable genetic markers that can be used to establish more distant relationships.
There’s another key difference between the two approaches, says Kieren Hill, head of the DNA lab at ICMP: “The difference from what we do is that our data is stored on our own servers.” The database of the organization is private and cannot be viewed by law enforcement agencies. In contrast, GEDmatch is online software that can be used by anyone, including law enforcement agencies investigating specific violent crimes.
That’s the reason for Miller’s privacy concerns. Miller says adding more black profiles to the database will give law enforcement more opportunities to investigate blacks — for example, if police use the GEDmatch profiles to link the relatives to DNA found at modern crime scenes. “You’re not just putting yourself in danger. It’s your parents, your cousins, your children, your unborn offspring, your whole family tree,” he says.
Even for people who have never committed a crime, uploading genetic data to a public website poses risks. DNA samples from crime scenes don’t necessarily come from perpetrators – they could be left by innocent bystanders. Or a person may be a close enough match to be implicated in an investigation, even if they are actually just a relative of the person involved.
But GEDmatch has its advantages. It contains the profiles of more than 1.3 million people, while ICMP collected around 120,000. The more profiles that are available, the greater the likelihood that researchers will be able to identify the Tulsa victims. “It’s the most powerful tool available,” says Hellwig.
It is also more consistent with distant relatives. The Tulsa Massacre happened a century ago, and descendants of the victims may be living anywhere now. The GEDmatch database is international and relies on SNP matching, which works for these looser connections.
In contrast, the ICMP works on recent events in specific geographic areas; In many cases there are living family members who can provide samples. The STR tests the group uses typically require three reference samples from a missing person’s parent, child, or sibling to establish a match. Since only a few first-degree relatives of Tulsa victims are still alive, such attribution is not possible.