Direct-to-consumer genealogy companies like Ancestry, FamilyTreeDNA , 23andMe, etc, give your DNA information to all law enforcement agencies.
Forensic genetic genealogy is the emerging practice of utilizing genetic information from these companies to help identify suspects or victims in criminal cases.
As of September 2021, the use of this practice has led to the discovery of over 150 suspects of murder and sexual assault.
The investigative power of genetic genealogy revolves around the use of publicly accessible genealogy databases such as GEDMatch and FamilyTreeDNA.
On GEDMatch, users are able to upload their genetic data from any direct-to-consumer company in an effort to identify relatives that have tested at companies other than their own.
Identifying unknown subjects through investigative genetic genealogy is done through the use of analysis of identity-by-descent (IBD) segments of DNA that indicate shared ancestors.
The most common type of forensic DNA profiling today for criminal cases and other types of forensic uses is called “STR” (short tandem repeat) analysis. These markers can be used to establish identity of missing persons, confirm familial relations, and link persons of interest to crime scenes.
Law enforcement agencies upload crime-scene genealogy data to these databases and try to locate relatives of potential suspects.
Family tree assembly and analysis of demographic identifiers is then carried out by genetic genealogy experts, either working directly for law enforcement agencies or through one of the many US companies that have been set up to work on these cases.
Parabon Nanolabs is the most well known company working in this field. By January 2021 Parabon claimed to have used genetic genealogy to produce an investigative lead in over 200 cases.