NY Times: Most White Americans’ DNA Can Be Identified Through Genealogy Databases by Heather Murphy:
And, of course, it can be subpoenaed by the government.
The science involves a search for third cousins. To identify a person through a DNA sample, an investigator uploads a previously analyzed genetic sequence to a database. The goal is to find someone who shares enough DNA to place them in the third cousin or closer range. Most of us have at least 800 people out there, somewhere in the world, who fall into this category. So long as one of these people is in a database, a skilled sleuth may be able to use other publicly available information to start building a family tree and figure out the person’s actual identity.
That technique has been used in recent months to identify more than 15 suspects in murder and sexual assault cases. The breakthroughs began in April with an arrest in the case of the Golden State Killer, who terrorized California with rapes and murders in the ’70s and ’80s. Other successes soon followed. A truck driver in Washington State was charged with the murder of a Canadian couple in 1987; a DJ in Pennsylvania was charged with the murder of a teacher in 1992.
Watching these developments, Dr. Erlich wondered about the odds of identifying any given person through cousins’ DNA in one of these databases.
NPR: Easy DNA Identifications With Genealogy Databases Raise Privacy Concerns by Rob Stein:
Police in California made headlines this spring when they charged a former police officer with being the Golden State Killer, a man who allegedly committed a series of notorious rapes and murders in the 1970s and ’80s. Authorities revealed they used DNA from a publicly available genealogy website to crack the case. Since then, police around the country have started doing the same sort of thing to solve other cold cases.