Genetic privacy eroding fast with growth of ancestry databases

Henrietta Strickland
October 14, 2018

Sending your DNA off to a genealogy company like 23 and Me and filling the gaps in your family tree has become a fascinating little pastime for tens of thousands of people, and has even spawned TV shows like Finding Your Roots, which often draw surprising connections between celebrities and historical figures (like Tina Fey and Benjamin Franklin).

And the way the genomic genealogy business is booming, that number is slated to jump to more than 90 per cent in the not-so-distant future.

Only 2 per cent of a population needs to be on a genealogy database to link nearly everyone to a third cousin. 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.

His and Erlich's studies "are both about this principle that connecting multiple databases reveals information that's not contained in either databases and that might not be intended by the people who have made those databases", he said. This proved that the method can be replicated using different databases, he said.

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.

This is where direct-to-consumer genealogy services shine - and they are big business.

As of April this year, more than 15 million people have used genome testing kits, with 7 million of those conducted in 2017.

With some basic assumptions about what kind of data would be available for a criminal suspect, the researchers calculated they could pare down the possible identity of the initial person to just 16 or 17 people.

The researchers targeted shared IBD segments that would correspond to second, third or fourth cousins.

By eliminating possible relatives by sex, age or residence, they landed on Joseph James DeAngelo, whose DNA they discreetly obtained from a vehicle door handle and his trash.

Police had DNA from DeAngelo's alleged crimes, but it didn't match with anyone in their forensic databases. There, they found some of DeAngelo's relatives, and painstakingly reconstructed his family tree.

This narrowed down their search for a suspect.

Then they uploaded his DNA sample to a free website called GEDmatch, which allows users to post DNA test results in text format.

Between April and August this year, at least 13 cases were reportedly solved with similar long-range familial searches.

Think of foreign governments using this technique to track down American citizens, he said.

This isn't Dr Erlich's first foray into genetic tracing.

With the recent rise in genealogy databases, could they harness those resources to trace anyone from their genome?

According to Erlich: "When the police caught the Golden State Killer, that was a very good day for humanity". They also suggest that consumer genetic companies adopt a better strategy of encryption so that there is a "technical means to differentiate between legitimate and illegitimate searches". They found two: one in North Dakota and one in Wyoming. They found 10 children and hundreds of grandchildren and great-grandchildren.

The researchers started with the 1.28 million participants on the MyHeritage site at the time they did the work.

The authors said the same process would work for about 60 percent of Americans of European descent, who are the people most likely to use genealogical websites, Erlich said.

"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.

Dr Curtis said that a technological platform will be an essential part of the solution, but "there won't be a magic bullet".

McGuire said there's an active legal debate about whether police should be able to "go on a fishing expedition" using DNA genealogy websites without a warrant.

Other reports by Click Lancashire

Discuss This Article