Familial DNA Searches May Make You Think Twice About Signing Up With Private Genetic Services

from the running-in-family dept

Using DNA found at the scene of a crime to identify the guilty party is pretty routine these days, but, as Mike discussed many years ago, police have been getting more aggressive in going much further: carrying out "familial" DNA searches on privately-held genetic databases. That link is to a recent Wired article that concerns the case of Michael Usry, who became a suspect in a 1966 1996 murder case because of his father's DNA:

Detectives had focused on Usry after running a familial DNA search, a technique that allows investigators to identify suspects who don’t have DNA in a law enforcement database but whose close relatives have had their genetic profiles cataloged. In Usry's case the crime scene DNA bore numerous similarities to that of Usry’s father, who years earlier had donated a DNA sample to a genealogy project through his Mormon church in Mississippi. That project’s database was later purchased by Ancestry, which made it publicly searchable -- a decision that didn’t take into account the possibility that cops might someday use it to hunt for genetic leads.
Using general similarities as the yardstick rather than more exact matches means that false positives are more likely -- as in this case, when Usry's own DNA proved he had nothing to do with the murder. Those similarities were only found because his father's DNA was in a privately-held genetic database that the police could access. That's unusual, but becoming more common as services like Ancestry.com and 23andMe gather many more DNA samples.

According to an article on Fusion.net, Ancestry now has over 800,000 samples, while 23andMe has a million customers (Ancestry says that a more up-to-date figure is 1.2 million members in its database). Those are significant holdings, and it's only natural that the police would try to use them to solve crimes; both companies confirm that they will turn over information from their databases to law enforcement agencies if served with a suitable court order. A more recent post on Fusion.net notes that 23andMe has produced its first transparency report (direct link, but Techdirt readers outside the US may have to use the Google cache version for reasons that are not clear.) The report shows that a total of four requests were received from the US authorities, concerning five 23andMe customers, and indicates that the company was successful in denying those requests, without giving details.

Although understandable, this kind of access is problematic for people who sign up for these services, for reasons made clear by the Usry case. The DNA that goes into the database affects not only the donor, if a rough match to crime materials is found by the police, but many close relatives whose genetic make-up is necessarily similar. As a result, it's entirely possible that completely innocent people might have to go through the traumatic experience of being a suspect just as Usry did before more precise tests ruled him out.

That's unfortunate, because it adds a complicating factor to the decision about whether to provide DNA to interesting and innovative services like Ancestry.com and 23andMe: doing so means future generations might be put at risk of erroneous police interest. The only way to prove their innocence would be to hand over their DNA to the authorities for detailed testing, which then raises the question of what happens to it afterwards.

Follow me @glynmoody on Twitter or identi.ca, and +glynmoody on Google+

Filed Under: dna, government, law enforcement, surveillance, transparency
Companies: 23andme, ancestry.com


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  1. identicon
    annonymouse, 22 Oct 2015 @ 6:18am

    Yes your honour the match has a certainty of one in a million.
    Would the prosecution please present the other matches then?
    What other matches?
    Well for one the tristate area population is 380 million and I at least did not fail grade school math.
    ....
    Some time latter.
    ....
    Judge Judy finds local prosecutors guilty of all crimes due to overwhelming DNA evidence.

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