Saturday, September 21, 2019

Police Genetic Genealogy at GEDmatch: Is Opt-in the Best Policy?

With over a million DNA scans in its database, GEDmatch has been instrumental in the success of genetic genealogy searches in criminal investigations. The genealogy website
provides applications for comparing your DNA test results with other people. There are also applications for estimating your ancestry. Some applications are free. More advanced applications require membership in the GEDmatch Tier1 program at $10 per month.
By uploading the text file of genetic data from a direct-to-consumer genetic testing company such as 23andMe or Ancestry.com, to a publically accessible database such as GEDmatch, genealogy enthusiasts can discover whether they have large blocks of DNA in common with other individuals who have uploaded their data. Extensive haploblock matching might reflect membership in the same family tree.

Police have used this service to identify possible relatives of the unknown individuals whose DNA was recovered from a crime-scene. Ordinary genealogy research into various records may lead to the common ancestor and then back down to the descendants -- including the one who left the crime-scene DNA.

This process of genetic genealogy for criminal investigations attracted extensive publicity, leading to a series of changes in GEDmatch's policies. At first, the DNA data from all participants (who chose to make their data available for searches by others) was open to law enforcement trawls. Later, the website's users could designate their data as not available for criminal investigations but still open for searches by the general public. In other words, they could opt-out of this one use. Then, the policy became opt-in only. Unless a participant affirmatively chooses to make his or her data available for criminal investigations, it is not included in trawls for police who identify themselves as such.

If police respect these policies, GEDmatch may be useless to them. In the first three weeks since GEDmatch moved to the restrictive policy, only 50,000 people opted in. CeCe Moore, the genetic genealogist with Parabon NanoLabs, which has scored the most successes for police, reported that the crime-scene uploads in that period stopped producing usable matches. "It’s basically useless now," said Moore. "Our work on any new cases is significantly stalled."
Does the opt-in policy go too far? GEDmatch encourages people to use an alias. Users can be contacted, but the individual inquiring won’t find them unless they choose to respond, and anyone can take his or her information off GEDmatch at any time. However, when there is a potential lead to a crime-scene sample, it would be easy for police or prosecutors to issue a subpoena or secure a search warrant to find the email address if not the name behind the alias.

By the way, the owner of GEDmatch said that he is considering charging police a fee to use the website. Unless the database accessible to police returns to its earlier searchable size of a million or so, he may not have many such customers.
C.J. Guerrini et al., Should Police Have Access to Genetic Genealogy Databases?, PLOS Biology, Oct. 2, 2018, 16(10): e2006906.

We conducted the survey online using Amazon Mechanical Turk (MTurk) ... . We restricted participation to individuals who were 18 years of age or older and located in the United States and paid them US$0.25 for taking the survey. ... [T]he majority supported police searches of genetic websites that identify genetic relatives (79%) and disclosure of DTC genetic testing customer information to police (62%), as well as the creation of fake profiles of individuals by police on genealogy websites (65%) (Fig 1). However, respondents were significantly more supportive of these activities (all p < 0.05) when the purpose is to identify perpetrators of violent crimes (80%), perpetrators of crimes against children (78%), or missing persons (77%) than when the purpose is to identify perpetrators of nonviolent crimes (39%).

My note: MTurk respondents may not be representative of users of GEDmatch.

SOURCES