To read this article in full, hit here This article appeared on Grunge by Aaron Homer.
Back in 1958, researchers James Watson and Francis Crick discovered the basic, double-helix structure of the DNA molecule, forever changing our understanding of genetics (via National Library of Medicine). In addition, this discovery paved the way for advances in DNA technology, which have led to things like commercial ancestry DNA testing and the use of DNA in forensics — solving crime by matching the DNA found at a crime scene to a suspect's DNA.
In the past few years, those two technologies have merged, in a manner of speaking, providing police with a new method of solving crimes. This is done not by identifying a suspect directly via his or her own DNA, but by identifying people who may be related to a suspect via DNA analysis and going from there. "The power of this new partnership between genetic genealogy and law enforcement has unlocked one of the biggest, if not the biggest, crime-fighting breakthroughs in decades," notes genealogist CeCe Moore, via the Forensic Technology Center of Excellence.
As of September 2022, this avenue of investigation has led to the resolution of several hundred criminal cases once considered cold (via Phys.org).
HOW FORENSIC GENETIC GENEALOGY WORKS
There are two methods that police can use to identify a criminal suspect through DNA, according to Genealogy Explained. The one we're all most familiar with, and which is bound to inform the plot of at least one TV procedural per week, is the most direct. In essence, a criminal suspect leaves behind something containing their DNA — a strand of hair, for example, or a drop of blood. That sample is compared to a sample from a possible suspect — perhaps law enforcement got a warrant to obtain one by, say, taking something from their trash. If the DNA is a match, then authorities have their man, so to speak.
The second method is more indirect. In essence, authorities take a DNA sample from a crime scene and then compare it to the millions of samples in a nationwide database of criminal genetics — the Combined DNA Index System, or CODIS — as well as those from regular people who used commercial ancestry DNA tests and whose profiles were uploaded into a database called GEDmatch (per the International Symposium on Human Identification). Authorities will then use this to match people who may be genetically close to the suspect — siblings, parents, cousins, and so on. (Do note that the preceding explanation is bare-bones and leaves out considerable scientific, procedural, and legal nuance.)
