Forensic investigative genetic genealogy: what is it?
Forensic investigative genetic genealogy (FIGG) is in the news again, most recently because of its relevance in the case of the disappearance of Nancy Guthrie, the 84-year-old mother of “Today” anchor Savannah Guthrie. Sources report that after a failure of finding a match in the CODIS database, FIGG is being used to attempt to identify a mixed DNA profile found inside the home and not connected to Guthrie family members.
What are CODIS and FIGG? In today’s short post, I’ll provide a quick overview of these two acronyms and their application in DNA testing and analysis for criminal investigations. For further learning, you can read about FIGG or listen to DNA Clarity and Support podcast guest J.C. Kenney, an author who researched and incorporated FIGG into the story of fictional investigator Allie Cobb.
What is forensic investigative genetic genealogy?
FIGG combines DNA science and traditional “DNA detective” work to identify unknown victims or perpetrators of a crime. This is done by comparing crime-scene DNA (or the remains of a discovered person, often referred to as a “John Doe,” “Jane Doe,” or “Baby Doe”) against profiles in certain consumer genealogy databases. Trained genealogists (often members of law enforcement teams who have received additional training in DNA and genealogy) build family trees for the unknown person whose DNA sample was found. These trees are built using distant matches of the mystery person and a combination of pre-built trees of DNA matches, public records, and historical documents. By narrowing down branches of the family tree and tracing living relatives using online information, the investigator reaches a smaller group of likely candidates. Using the people in the tree as “hints,” investigators narrow down to perhaps one candidate or a small group of them, and then attempt to obtain separate and new DNA samples (or in the case of a Doe, their suspected living relatives) to analyze and compare to the sample they already have.
This approach relies on reliable DNA laboratories and trained researchers who can make meaningful connections between a DNA profile and the family trees that emerge.
Which consumer DNA sites or organizations allow law enforcement use for FIGG cases?
There are four at this time, and only one of these (FamilyTreeDNA) is a consumer DNA testing company that receives consumer biological samples and processes them into a computerized data file. The other three (GEDmatch Pro, DNA Solves, and DNA Justice) are sites that allow users to upload computerized DNA files they have obtained somewhere else.
AncestryDNA, 23andMe, and MyHeritage have disallowed use of their databases for the purposes of FIGG at this time. The current terms of service do not restrict customers from downloading their raw data files and uploading them to these other sites.
How does the CODIS database come into play?
The Combined DNA Index System (CODIS) database was developed by the FBI as a repository of DNA profiles, initially piloted in 1990 and rolled out nationwide in 1994. There are three levels: local, state, and nationwide. CODIS does not store a person’s entire genomic profile; it stores a select set of roughly 20 STR (short tandem repeat) markers.
Prior to the emergence of FIGG in 2018, CODIS was the sole source for criminal investigators seeking to research DNA profiles associated with crime scenes. According to the Pima County Sheriff’s Office, CODIS was checked first to see if there was an existing profile matching DNA samples connected to the Nancy Guthrie case; no matches to DNA profiles in CODIS were found.
For which kinds of criminal cases can FIGG be used?
There has been a lot of discussion since 2018, when FIGG was first used to solve the Golden State Killer case, around the “slippery slope” of allowing law enforcement into consumer databases. Terms of use at consumer DNA test companies have changed over time, and some companies have tightened restrictions on the use of the data they provide (genealogical records and DNA matches), while others have loosened them.
Ethical arguments around FIGG tend to focus on the boundaries of what is and isn’t acceptable: which crimes are considered “bad” enough that they should allow law enforcement and investigators to use FIGG and consumer DNA matches to research? Where do you draw the line? If someone breaks in, steals money from a cash register, and leaves behind a DNA sample, could consumer databases be used? Right now, no; a crime must involve a death or signs of aggravated assault to be eligible. These lines can be expected to change and evolve over time.
For more reading about forensic investigative genetic genealogy, visit ISOGG or find resources on WatershedDNA.com.
