The Doubled-Edged Sword of Genetic Genealogy

April 10, 2022

Everyone has heard of DNA. DNA is the building block of human life. It’s what makes us who we are. Once a novel concept, DNA is now a common term used in everyday conversation. DNA technologies have been further developed in recent years, helping to solve crimes that once seemed impossible to solve. But with those advancements also come concerns about privacy.

A massive development in DNA technology occurred in 1953, when a team of scientists discovered DNA’s (formally known as “deoxyribonucleic acid”) double helical structure. Thirty years after that discovery, scientist Kary Mullis developed the Polymerase Chain Reaction (PCR), which would revolutionize DNA testing technology. The PCR method does not require nearly as much DNA material as previous methods of DNA testing. Thus, DNA profiles could be developed with only small amounts of DNA, like those amounts left by perpetrators at a crime scene.

Another major development in DNA testing was the creation of the FBI’s Combined DNA Index System (CODIS) in 1998. This database is used by all fifty states, at the federal, state, and local levels. DNA from crime scenes is input into the CODIS database. Then, when new crimes are committed, DNA from those crime scenes is added to the CODIS database as well. Investigators hope there will be a “hit,” meaning the DNA from the new crime scene matches previously collected DNA and can be linked to a DNA profile. Since its creation, CODIS has been used in more than 545,000 investigations.

New forms of DNA testing have developed over the years. Perhaps the most buzz-worthy in recent years is genetic genealogy. In genetic genealogy, “[t]he traditional techniques of genealogy—tracking-down records like birth and marriage certificates, census data, and newspaper obituaries—along with modern methods like Facebook stalking are then combined with DNA profiles to build a huge family tree of people who might be related to the perp[etrator].” The discoveries of Y-DNA, which is inherited from one’s father, and mitochondrial DNA, which is inherited from one’s mother, helped create the field of genetic genealogy by providing more information about specific ancestral lines.

So far this year, multiple cold cases have been solved through the use of genetic genealogy. One case involved the murder of a young woman 42 years ago in New York. Another case involved the murder of a young girl 58 years ago in Pennsylvania.

Genetic genealogy developed in the early 2000s and gained traction with the increased use of online genetic databases by the general population. One well-known database is run by the popular company 23andMe. For this company, a customer sends their DNA to 23andMe by spitting into a vial at home and mailing the vial to the company’s laboratory. Then, the laboratory runs the DNA and delivers an ancestry report within weeks.

However, by uploading this genetic data, it can be accessed by the public, including law enforcement. One of the most famous cases to use genetic genealogy in the past few years was the case of the Golden State Killer, now known to be Joseph James DeAngelo, Jr. DeAngelo evaded California police across the state for decades. He was finally caught in April 2018, after law enforcement tracked him down through one of his distant cousin’s DNA profiles on a website similar to 23andMe.  

Not everyone approves of genetic genealogy, particularly those whose genetics have been uploaded to databases unwillingly. When family members—even distant family members—upload their DNA to databases in search of information about their ancestry, they are uploading information about everyone to whom they are related.

Not everyone approves of genetic genealogy, particularly those whose genetics have been uploaded to databases unwillingly. When family members—even distant family members—upload their DNA to databases in search of information about their ancestry, they are uploading information about everyone to whom they are related. A pioneer in the field, CeCe Moore, describes the problem that underlies this type of DNA technology: “It’s about how we can control something that is uniquely ours—and yet to entirely ours to control. It’s about data that is personal yet transpersonal. . . . with consumer DNA sites, the real breach is simply that the data exists in the first place.” And so much data already exists. Moore says, “It doesn’t really matter if you’re opposed: It’s a collective decision that’s already been made . . . 30 million people [the number of people who have taken commercial genetic tests] made that choice for everybody else.”

In the future, law enforcement will likely want to continue using this method of investigation, and some citizens will likely resist this as an infringement on their rights. Thus, this conflict between using genetic genealogy in law enforcement and protecting individuals’ privacy rights will inevitably continue to make headlines in the coming years and may soon end up in the courtroom.

Sarah Cheeley

Sarah is a graduate of the University of North Carolina at Chapel Hill, where she majored in both History and Sociology. On JOLT, Sarah is currently a staff member and will serve as the Senior Articles Editor for Volume 24. Sarah is interested in pursuing a career in litigation. See the author’s previous blog post here.