Forensic Genetic Genealogy
A law enforcement method that identifies unknown people by finding DNA matches with their relatives in public genetic databases used for personal genealogy.
Not to be confused with: Forensic Investigative Genetic Genealogy
See also: Forensic Investigative Genetic Genealogy
Forensic genetic genealogy is a specialized technique used by law enforcement to identify unknown persons by comparing their DNA with public genetic databases. It begins by finding third-cousin or closer matches among thousands of users who have submitted DNA for personal genealogy or adoptee searches. If a close relative has opted into a database, investigators can trace family lines to pinpoint the unidentified individual, even if that person never submitted their own DNA.
What this means in real life
Police found DNA at a decades-old murder scene but had no match in criminal databases. They uploaded it to a public ancestry site, found a distant relative, then worked backward through that person's family tree to identify the actual perpetrator—someone who had never been arrested.
What it isn’t
It is not the same as traditional DNA fingerprinting, which matches crime-scene DNA directly to a suspect's profile in a law-enforcement database. Forensic genetic genealogy works backward through family connections when no direct match exists.
Commonly misused online
People often assume it means police can instantly identify anyone from a DNA sample, when in reality it requires painstaking genealogical research and typically identifies relatives first, not the person themselves.