September 22, 2023

In other cases, detectives can secretly collect DNA from a relative of a suspect by testing an item that the relative threw in the trash.

New Maryland law states that when police officers test the DNA of “third parties” – anyone other than the suspect – they must first obtain written consent, unless a judge approves a misleading collection.

Investigators cannot use any of the genetic information gathered from the suspect or third parties to obtain information about a person’s psychological characteristics or susceptibility to illness. At the end of the examination, all genetic and genealogical records created for this purpose must be deleted from the databases.

Perhaps most momentous, Maryland researchers interested in genetic genealogy must first try their luck with a government-run DNA database called Codis, whose profiles use far fewer genetic markers.

Mr Holes said that part of the law could have tragic consequences. In ancient cases, he pointed out, DNA evidence is often badly degraded and fragile, and each DNA test uses up some of this valuable sample. “Essentially, the law could make me kill my case,” he said. Given the speed with which DNA technology is advancing, it is unwise for a law to mandate the use of a certain type of test.

However, other experts cited this provision as critical, as the potential invasion of privacy is far more serious for genetic genealogy, which gives law enforcement access to hundreds of thousands of genetic markers, than it is for Codis, which only uses about two dozen markers.

This research is “the equivalent of the government going through all of your medical records and all of your family records to identify you,” said Leah Larkin, a genetic genealogist who runs a consulting firm in the San Francisco Bay Area that focuses largely on that Essential focuses on helping adoptees and others find their biological relatives. “I don’t think people know exactly how much is in your genetic data.”