DNA profiles

When posted, you don’t know who gets to see it

I know it’s hard to argue about the privacy rights of a possible serial killer and rapist.

But privacy rights are pretty much the same for everyone.

And that takes us to the methods used to identify a suspect in a longrunning serial murder and rape case in California, an individual known as the Golden State Killer.

Police arrested 72-year-old Joseph James DeAngelo for 45 rapes and a dozen killings. They used a website, GEDmatch, which allows people to upload their own genetic information to make a big pool to search out lost relatives. They had DNA from the Golden State cases, but hadn’t been able to connect it to anyone using standard police and government DNA databases.

Using the open source public site, they were led to a genetic marker that matched two third or fourth cousins, allowing investigators to build a family tree — one with more than 1,000 individual entries — that eventually pointed them in DeAngelo’s direction. You might say “great police work.” You might also point out that, though the method the police used was legal, it was also a little unsettling.

Police don’t need a search warrant to search the trash you leave out at the curb.

And they didn’t need a search warrant to search the genetic data that people had loaded into a public site, either.

“We understand that the GEDmatch database was used to help identify the Golden State Killer,” a statement from the company said. “Although we were not approached by law enforcement or anyone else about this case or about the DNA, it has always been GEDmatch’s policy to inform users that the database could be used for other uses, as set forth in the Site Policy ... While the database was created for genealogical research, it is important that GEDmatch participants understand the possible uses of their DNA, including identification of relatives that have committed crimes or were victims of crimes.”

There are 900,000 DNA profiles on GEDmatch’s site: bit by bit, profile by profile, the site is building an evermore-accurate road map.

You might not want your DNA profile on their site, and you might not agree for them to use it, but if other members of your family are willing to put themselves out there genetically, you’re unavoidably along for the ride.

The possible uses don’t end with crimes, after all; pools of public DNA information could be used to identify things like family groups that have higher hereditary risks for diseases — and that insurance companies might not want to provide health coverage for.

There’s also the problem that, while we’ve all been schooled to believe DNA evidence is virtually infallible, the type of familial DNA work used in this case creates enough false positives that some states have banned or restricted its use. Fact is, it casts a wide net, and there’s a lot of work that has to be done to narrow down potential suspects. (The public records DNA search for the Garden State killer originally targeted a different man in Oregon, for example. He was ruled out using a sample of his DNA, obtained under court order.)

I understand the argument that there’s now the potential to bring a truly vile criminal to justice.

But it is a case of the end justifying the means — and when you open that particular gate, the means can get used for lots and lots of other things.

And if enough of us decide to post information for everyone to see, well, all of our private lives will get a lot less private.

To repeat? The enemy: us.

“We have met the enemy and he is us.” — Walt Kelly’s cartoon character, Pogo