A new study estimates that about 60 percent of the USA population with European heritage may be identifiable from their DNA by searching consumer websites, even if they've never made their own genetic information available. Because most genetic test companies allow their customers to download files of their raw genetic information, this has spurred third-party services from other companies, including GEDmatch, which allows people to upload their raw data for additional analysis, such as ancestry searches.
"We're not saying we shouldn't let law enforcement search databases, but instead have a conversation with them, find out if their request is legitimate, and then maybe you sign paperwork to let them do it", Dr Erlich said. Eventually, that can point to someone whose DNA is then found to match the original sample.
With DNA databases "you need just a minute fraction of the population to really identify many more people", said Yaniv Erlich of Columbia University, an author of the study.
The team of researchers at genealogy website MyHeritage and at Columbia University in NY who wrote this latest study said that the police are using these databases as tools to catch the miscreants.
Further, they found that people with Northern European ancestry were easiest to link up.
By comparing the DNA of all three relatives, Erlich's team was able to find a common ancestral couple that were the Utah woman's great-grandparents.
A similar cross-referencing technique was recently used to break the long-cold case of the Golden State Killer after a relative's DNA popped up on a genetic testing site.
A person and his or her third cousin have the same great-great-grandparents.
"When the police caught the Golden State Killer, that was a very good day for humanity", Erlich said. For over 60% of the individuals within the dataset, a family member with matching DNA segments roughly corresponding to a third cousin relation or closer was also found. "We were able to find matches between samples in databases of non-overlapping genetic markers more than 90% of the time when they were samples from the same individual and around 30% of the time when they were samples from close relatives".
Websites are getting very close to that, said Erlich, noting that MyHeritage now has more than 1.75 million participants. "Based on these results, we propose a potential mitigation strategy and policy implications to human subject research", the report says.
Two DNA experts unconnected to the study said third and fourth cousins can both lead to identifications.
"Because the average person has so many of these distant cousins, it becomes reasonably probable that one or more of them is in a publicly searchable database, even if only a small fraction of the United States population is included", Graham Coop and Michael Edge, DNA experts at the University of California, Davis, who did not work on the study, wrote in a statement to The Associated Press.
A new study argues that more than half of Americans could be identified by name if all you had to start with was a sample of their DNA and a few basic facts, such as where they live and how about how old they might be.
They said their findings, published in the journal Science, raise concerns about privacy. Should anyone other than law enforcement be allowed to conduct such searches? And under what circumstances should they be permitted? One of his cousins had taken a commercial DNA sequencing test and the information had led the police to DeAngelo whose DNA matched with those from the samples found in the crime scenes of murders and rapes all over California. Furthermore, using publicly available genealogical records, Erlich et al. demonstrate that once one or more relatives are found, the identity of an individual can be determined through family lineages combined with specific demographic information, such as approximate age or area of residence.
Amy McGuire, a professor of biomedical ethics at the Baylor College of Medicine in Houston, said that police searches using DNA and genealogy websites have sometimes pointed to an incorrect person.