In this book, we’ve deeply explored the ways DNA and DNA fingerprinting have been used in both the forensic and medical spheres. However, once that fingerprint is developed, it must be matched with a DNA profile already collected. Unfortunately, CODIS matches are hard to come by as there is a high chance the criminal was never arrested before, and thus, their DNA profile was nowhere to be found. For our last topic, we revisit a solution to this problem – the intersection of the DNA profile with modern technology.
When presented with a problem of profile matching, investigators turn to forensic genetic genealogy (FGG). In what the Department of Justice calls the culmination of “traditional genealogy research and DNA analysis,” FGG unlocks a new dimension in the pursuit of justice. Through FGG, investigators take a developed DNA profile and look to compare it within genealogy databases. After uploading their sample, investigators try to build a family tree to identify relatives of unknown suspects. Sometimes, the most “likely” match is made a suspect, but other times, investigators track down relatives and are eventually led to the perpetrator. This innovative method holds the potential to illuminate the darkest corners of unsolved cases, revealing the faces behind crime’s masks.
But first, specific kinds of DNA can be tested to reveal specific kinds of relationships. The most common commercial test is autosomal DNA testing, as it analyzes almost the entirety of our DNA, except for the X and Y sex chromosomes. Y chromosome testing specifically focuses on the Y chromosome – one found only in males. This allows genetic ancestry to be traced from the father. On the other hand, mitochondrial DNA is passed down from the mother, so mitochondrial DNA analysis allows matriarchal lineage and ancestry to be discovered. In both cases, investigators can identify whether their suspect shares any common maternal or paternal with other users on the databases. However, most genealogy databases have much more samples with “Caucasian DNA components,” as they predominantly have more information on genetics for people of European descent, which may sometimes make identifying a suspect of a highly represented ethnicity easier than others (Sequencing).
Aiding law enforcement in utilizing genetic genealogy is Parabon Nanolabs, a Virginia-based company that specializes in DNA phenotyping – using a person’s DNA to predict their physical characteristics. The company has partnered with GEDmatch, an online service that compares autosomal DNA files across a multitude of databases (and which grew in popularity after it was used to catch the Golden State Killer in 2018). “After an analysis, GEDMatch produces a list of family relatives who have also opted into its service, from immediate parents to fourth and fifth cousins, along with their contact information” (CNN). Just after the Golden State Killer’s arrest, the genetic genealogy work of Parabon Nanolabs and CeCe Moore – one of the world’s most prolific genetic genealogist – helped narrow down a suspect list of another decades-old rape and murder to two brothers, both of whom were investigated. However, Parabon Nanolabs’ DNA phenotyping is even more revolutionary. With support from the US Department of Defense, Parabon Nanolabs can now predict physical attributes such as “eye color, hair color, skin color, freckling, and face shape in individuals from any ethnic background, even individuals with mixed ancestry,” all included and presented to investigators in their Snapshot Prediction Results Composite Profile (Parabon Nanolabs). Many of these profiles have supplanted police sketches and are thus sent to the media by law enforcement occasionally. Traits that are more highly linked to heritage, such as eye and hair color, are more accurately predicted (some with 99.99% confidence). However, these profiles, especially for men, cannot account for attributes acquired later, like facial hair, and cannot account for age. Furthermore, only around 40-45% of facial structure can be determined by DNA phenotyping. Parabon’s DNA phenotyping has also helped investigators identify previously unidentified remains of several women, giving closure to the families. Since 2018, Parabon has helped solve over 200 cold cases, at a rate of approximately 1 per week.
So, is our genetic information safe in these commercial DNA databases? With concerns around privacy, genetic testing sites like 23andme declare they choose to use “all practical legal and administrative resources to resist requests from law enforcement,” while Ancestry states that “it only releases customers’ information in response to a trial, grand jury or subpoena” (CNN). Additionally, the raw DNA data itself is never exposed. Back in 2019, a Florida detective obtained a warrant to “penetrate GEDmatch and search its full database of nearly one million users.” Arrests were made after GED data, which contains over 1 million profiles, was searched and accessed without notifying users. This stirred up controversy and several prominent genetic genealogists argued about the ethics of such decisions. To the chagrin of many officers, GEDmatch eventually updated and tightened its policies, allowing law enforcement agents to only access profiles where users had consented to make their data “public” to officers. Furthermore, many are concerned that leaking genetic data from these sites may reveal sensitive health information, which could prevent an individual from receiving insurance if exposed. Similarly, leaked details about a person’s race and ethnic background could lead to discrimination during hiring.
Even with all these tools, success is nowhere close to being guaranteed. While we may share 50% of our DNA with our parents, and almost 100% with a twin, many leads for law enforcement start with 3rd or 4th cousins – of which on average, we have around 175. We share around 0.8% of our DNA on average with a 3rd cousin and there is a “2% chance that a given pair of third cousins will share no DNA at all” (UK Gov). As a result, it may still take a long time to track down a suspect from their relatives. In the case of the Golden State Killer, it took “several thousands of hours of genealogical research to identify the likely suspect,” even when the suspect pool had reduced to 20 individuals. And again, there is lesser information available on the ancestry and DNA of many non-European groups.
Currently, the Washington Attorney General’s Office has provided more than $290,000 to “assist local law enforcement agencies with felony cold case investigations through forensic genetic genealogy testing” (Associated Press). Genealogy research and testing are costly, but these funds are also a part of the U.S. Justice Department’s initiative to address the larger backlog of rape kit testing in the US.
According to Prison Policy, homicide victimization rates for black men, black women, and Indigenous women have been consistently higher than for other racial and ethnic groups, with Indigenous and Black women being especially vulnerable. Furthermore, black genealogists are often cautious of police use and have “deleted their profiles or opted them out of law-enforcement matching on GEDmatch” (The Atlantic). As CeCe Moore states, the more wary people are of investigative genetic genealogy, the less they will participate. Since then, genetic genealogists like CeCe Moore have been actively working to change the face of these cold cases by working on cases with more marginalized victims, such as people of color and sex workers.
Meanwhile, ancestry testing will continue to advance our understanding of the diverse populations of our world, paving the way for improved clinical predictions and investigative genetic research.
Sources:
https://sequencing.com/education-center/genetic-genealogy
https://www.cnn.com/2018/08/03/health/dna-genealogy-cold-cases-trnd/index.html
https://snapshot.parabon-nanolabs.com/phenotyping
https://www.theatlantic.com/science/archive/2021/01/genetic-genealogy-race/616171/
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