Understanding Genetic Genealogy Testing Without Fear
Written on
Human DNA is 99.9% similar across all individuals, from a newborn in the Congo to a Wall Street professional. However, the tiny percentage that differs can reveal a wealth of information about our heritage and familial connections.
Through the small unique portion of Autosomal DNA, one can trace ethnic backgrounds inherited from ancestors spanning five to ten generations. Autosomal DNA testing is inclusive of all genders, as it does not involve X or Y chromosomes. This testing not only helps identify living relatives with reasonable precision but also sheds light on our susceptibility to certain diseases and conditions. Currently, this information can be accessed for approximately $100 and from the convenience of home—what an exciting time to explore our ancestry!
But what if this sensitive data were misused? People often fear that insurance companies could increase premiums or deny coverage based on genetic information. There’s also a concern that previously unknown relatives might emerge, seeking a share of inherited wealth. In the worst-case scenario, one might find themselves or a family member implicated in a crime.
This is less likely than you think.
To alleviate these worries, it's essential to understand the operations of genetic genealogy companies.
The Major Players
Three primary companies dominate the direct-to-consumer genetic testing market: Ancestry, 23andMe, and FamilyTreeDNA (specifically their Family Finder product). MyHeritage is also gaining traction. Each company necessitates a saliva sample, which can be collected via a swab or a tube—hair, blood, or other bodily fluids are not applicable.
The procedures followed by these companies are fundamentally similar. First, they gather your saliva, then assess the DNA quality and compare it to a reference population to generate an ethnicity estimate. They subsequently match your sample against the results of others who have tested. After a few weeks, the findings are made available on their respective websites, and the saliva is securely stored, with options for destruction upon request.
Ethnicity Insights
You can uncover inherited ethnicities from roughly ten generations back through these tests. The companies analyze over 700,000 genetic markers known as Single Nucleotide Polymorphisms (SNPs), which indicate small genetic variations occurring over time. Each genetic region has a distinct frequency of these changes, represented by a reference panel.
The individuals in the reference panel are not your relatives; they have been specifically selected and tested to represent distinct ethnic groups, with well-documented family histories. The SNPs in your sample are then compared multiple times to ensure accuracy, resulting in a percentage range for your ethnicity estimate.
Each company's ethnicity estimate is unique due to varying reference populations, which may lead to different results.
Connecting with Relatives
You can discover relatives, referred to as “matches,” who share DNA with you. By comparing centimorgans—the measurement unit for DNA—you can estimate the closeness of your relationships. A match between a parent and child or siblings is almost certain, while you typically share DNA with only about half of your fourth cousins and those beyond.
Health Insights
Your DNA test may yield a report on predispositions to various health conditions, covering traits from eye color to genetic risks for diseases. These reports can also highlight beneficial traits, such as a gene linked to longevity. However, health reports are a contentious aspect of consumer DNA testing, and it's advisable to consult medical professionals to interpret these results accurately.
Raw DNA Reports
The leading DNA testing companies provide raw DNA reports that can be used with other platforms. If you examine this report, you will find a sequence of letters and numbers that are 99.9% identical to those of any other person. Unless you are a geneticist, this raw DNA data may not be engaging. However, you can upload these reports to other websites, such as GEDmatch.com, which could expand your genetic exploration.
GEDmatch Case Studies
Consider Suzy, who tested with Ancestry in hopes of locating a child she placed for adoption in 1976. Despite Ancestry's extensive database, her closest connection was a fourth cousin. She wisely uploaded her raw DNA to GEDmatch.com and found a match sharing 3400 centimorgans. This turned out to be her son, leading to their emotional reunion.
Now, let's look at Matthew, who received a 23andMe test as a gift. He was eager to find his Native American roots but found no evidence in the results. A college professor advised him to try GEDmatch, where he discovered a distant match linked to a cold case from before his birth. This connection revealed a long-held family secret, shaking his family to its core.
Both scenarios occur, with Suzy's being relatively common and Matthew's being rare. Yet, many individuals remain hesitant to explore their genetic connections due to fears of uncovering uncomfortable truths or facing insurance discrimination. Such concerns should not deter anyone from pursuing testing if they are aware of the safety measures in place.
Chain of Custody
The integrity of saliva sample submissions relies on a trust system. There is no official verification to confirm that the sample is indeed yours; it could come from any individual. Once received at the lab, the sample is identified only by a number, safeguarding your identity throughout the process.
You Maintain Control
Consider this: who was the individual linked to the Golden State Killer on GEDmatch? The answer is unknown to the public. Unless voluntarily shared, personal details remain confidential.
The testing company will protect your information on their site, but once you choose to upload to other platforms, the responsibility for security lies with you. Although Family Tree DNA has stated they will cooperate with law enforcement, this should not discourage you from testing. Knowing if you're related to a violent criminal can empower you to protect vulnerable family members.
It is not mandatory to upload your data to GEDmatch, and neither Ancestry nor 23andMe permits raw DNA uploads. Law enforcement would only be able to access crime scene DNA via court order, a rare occurrence.
The FBI operates its own database, CODIS, which utilizes Short Tandem Repeats (STRs) rather than SNPs, making them incompatible for comparison. If a familial connection exists, an expert genealogist will likely uncover the truth without requiring you to test again.
Understanding GINA
The health insights gained from genetic testing are invaluable, whether through personal or professional channels. The Genetic Information and Non-Discrimination Act (GINA) prohibits insurance companies from using genetic data to affect coverage decisions.
GINA also extends protection against employment discrimination based on genetic history. Should you face discrimination, you have a legitimate case for legal action.
Ultimately, there is no need for fear. Your DNA is not so exceptional that it could be exploited. If you're apprehensive, consider testing anonymously or seeking ethnicity results without opting into matching services. If you want to use GEDmatch but prefer to keep your results away from law enforcement, you can choose to opt-out. However, countless individuals—such as adoptees and families of crime victims—appreciate your willingness to engage in this genetic exploration.
Further Reading
- The Family Tree Guide to DNA Testing and Genetic Genealogy, Blaine Bettinger
- The Foundling: The True Story of a Kidnapping, a Family Secret, and My Search for the Real Me, Paul Joseph Fronczak