The Methodology of Forensic Genealogy
Forensic genealogy begins with a DNA sample obtained from a crime scene or unidentified human remains. This sample undergoes a process to generate a genetic profile, focusing on hundreds of thousands of single nucleotide polymorphisms (SNPs). Unlike traditional law enforcement DNA profiles, which rely on shorter, repetitive DNA sequences, SNP profiles provide a richer genetic blueprint for identifying distant relatives.
The generated SNP profile is then uploaded to public genetic genealogy databases, such as GEDmatch and FamilyTreeDNA, which allow law enforcement access. These platforms compare the unknown DNA profile against millions of profiles voluntarily submitted by individuals seeking to connect with relatives or explore their ancestry. The database algorithms identify potential genetic matches, ranging from close family members to more distant cousins, based on the amount of shared DNA.
Once genetic matches are identified, forensic genealogists begin traditional genealogical research. They construct extensive family trees for the DNA matches, using public records like birth certificates, death certificates, census data, obituaries, and historical documents.
This research often requires constructing multiple family trees and analyzing shared DNA segments to infer relationships. The goal is to narrow down the pool of potential individuals to a manageable number, typically focusing on those who would have been in the geographic area at the time of the incident. Law enforcement then uses these investigative leads to gather further evidence, which may include obtaining a direct DNA sample from a person of interest for direct comparison.
Solving Cases with Forensic Genealogy
Forensic genealogy is an investigative tool primarily used to generate leads in complex criminal cases that have remained unsolved. It is particularly effective in cold cases involving violent crimes, such as homicides and sexual assaults, where traditional investigative methods have been exhausted.
Beyond identifying unknown perpetrators, forensic genealogy is also instrumental in identifying unidentified human remains, often referred to as “John” or “Jane Does.” By developing a genetic profile from skeletal remains or other biological evidence and comparing it to public databases, genealogists can trace family lineages and provide names to individuals whose identities have been lost, sometimes for decades.
Forensic genealogy also helps exonerate individuals wrongly accused or convicted. By providing new leads or re-examining existing evidence with advanced genetic techniques, it can rectify past miscarriages of justice. This capability aids both crime prosecution and legal system accuracy.
It has identified suspects in decades-old murders and sexual assaults and provided identities for hundreds of unidentified decedents across North America. These cases often involve DNA evidence preserved for years, lacking a match in traditional law enforcement databases like CODIS.
Privacy and Ethical Concerns
The use of forensic genealogy raises privacy and ethical questions, particularly concerning genetic information submitted to public databases. A primary concern is the concept of consent, as individuals who upload their genetic data typically do so to find relatives or learn about their ancestry, not to potentially implicate themselves or their family members in criminal investigations.
When a DNA sample from a crime scene matches a distant relative in a database, that relative, and by extension their family, can become part of an investigation without their direct consent or knowledge. This “genetic dragnet” can extend to individuals who have never provided their DNA, as their genetic information can be inferred through their relatives, leading to concerns about “guilt by association.”
The broader implications for genetic privacy are a subject of ongoing debate. While some argue that sharing DNA with a public database implies a relinquishment of privacy, others contend that the scope of this implicit consent does not extend to law enforcement investigations. Concerns also exist about potential discrimination based on genetic information.
Calls for clearer regulations and guidelines in this evolving field are prevalent among policymakers and ethicists. Balancing its use to solve serious crimes with protecting individual genetic privacy remains a challenge. Some databases have implemented policies requiring users to opt-in for law enforcement searches, while others maintain broader access, highlighting the varied approaches to these privacy dilemmas.