Genetic genealogy uses a comparison of DNA testing with genetic databases to construct a reverse family tree to locate a suspect otherwise unknown to investigators, has emerged in recent years as law enforcement’s most powerful tool.
All it takes is a single strand of DNA to solve decades-old cold cases and identify suspects in current ongoing investigations.
DNA is extracted from something like a tooth or a fingerprint left on a car door handle and uploaded to a massive database, where it is compared with millions of other DNA profiles for similarities, known as “starting data points.” Those points are then used to build a family tree for each person.
“We look at the genetic relatives of our unknown sample,” genetic genealogist Misty Gillis, of Identifinders International and BirthParentFinder explained in an interview, “It gives us a list of all the DNA matches that they have, and it tells us how much DNA is shared with that person, an estimation of what their relationship could be with that person, whether it’s a first cousin, a second cousin or a third cousin.”
