Why your “Ancestry” test may be wrong
Can you trust the results from your ancestry test?
If you have recently received results from one of the many popular ancestry testing companies, you may be facing some questions you are earnestly seeking answers to. If your ethnic profile came back different than what you have been told, you may begin to wonder if you are really part of the family you thought you were (Am I adopted? – Do I have a different father? – Is my sibling really my sibling? – Do I have other family I didn’t know about?). These are common questions and ones you have a right to an answer to.
Journey Genetic Testing is here to help you on your path to understanding your true family relationships. Our company has performed DNA testing for thousands of people with the same questions as you have. However, before we go down this road together, please read the following information to help you understand how we are different from the testing you took through the ancestry companies.
How accurate are ancestry tests when it comes to determining ethnicity and genealogy?
The companies selling these services don’t share their data, and their methods are not validated by an independent group of scientists. There are not agreed-upon standards of accuracy. People have sent their DNA to several of these companies and found differences in the results—though not necessarily radical differences. So you have to look at the percentages you receive back with skepticism.
In comparison our affiliated DNA testing laboratories are AABB accredited. That means there is a standardized methodology and testing protocol followed by the labs. The testing and labs each undergo an intensive review of their procedures and policies annually to be certain they are in compliance. AABB accredited labs are the only facilities that can conduct DNA testing that is court admissible, due to their high standards. The results we deliver for home testing follow the exact same process, and has the same results, as our legally admissible tests do, however the collection process is different, so they are not generally accepted for legal purposes.
Why do the tests return different results?
Each company offering these services uses its own proprietary database of DNA samples called ancestry informative markers (AIMs) from current populations in Asia, Africa, Europe, and the Americas. From within those databases, they each select for a certain number of alleles—one member of a pair of genes located at a specific position on a specific chromosome—and in these spots, use the genetic variations known as single nucleotide polymorphisms (SNPs) as the basis for evaluating individuals. The markers—SNPs—are chosen because they have different frequencies across different geographical populations.
They compare SNPs with those most frequently associated with different populations in their reference database. The results are in no way definitive; instead each company uses common genetic variations as the basis for saying the probability is that 50 percent of your DNA is, for example, from North Europe and 30 percent is from Asia, based on how it compares to the information in its database. However, if you send DNA to a second company, you might get different results, because it has a different database. Studies that have compared ancestry databases have found poorer concordance with Hispanic, East Asian, and South Asian descent.
Some of the companies selling these testing services give you the option of learning about people who have similar SNPs to you, which may be why you have found us on your Journey. You can get a list of people who may appear to be part of your larger family ancestry, but that does not mean it is accurate, in large part because there is not a database of every single person’s DNA who is currently living, as well as at least two generations back.
What difference does it matter if the DNA testing process is not the same?
To compare our testing process with the process described above would be like comparing apples and oranges. Both test DNA, but have a different “taste.” Our testing process is STR (short tandem repeat) testing where we compare the DNA directly from two or more individuals to make a determination on their suspected relationship. Rather than suggesting the same person may be your uncle, your grandfather, a half sibling, or a cousin (all at the same time!), STR testing allows us to focus on the specific relationship in question with the DNA directly from those testing, for a reliable and accurate understanding of the likelihood of their relationship.
What else might make the results from an ancestry company inaccurate?
There’s a big chunk of data—actually the majority—that these genetics-testing services don’t use. Your DNA contains millions of SNPs, but these tests are selectively looking at certain genetic variations and use between 100 to 300 AIMs, which account for a small part of the SNPs that differentiate the human family. So even if a test says you are 50 percent European, really it can only report that half of those SNPs of your DNA looks to be European.
The results are further skewed by the fact that certain ancestry information markers used by any particular test may come from only your paternal line (Y chromosome) or your maternal line (mitochondrial DNA). Tests using these markers are less accurate.
In contrast, STR testing looks at genetic material from both the biological mother and father that was passed on to each of the specific people testing.
Finally, these testing services use DNA from modern populations in these regions to draw conclusions about people who lived in those areas hundreds, or even thousands, of years ago. It’s a big leap to assume that the particular SNPs used by the tests have remained constant for all that time.
You should understand that you are not matching your DNA to someone from hundreds of years ago. It’s also quite possible for someone who is African American to get ancestry test results that say they’re 75 percent European. That’s because the chosen ancestry-information markers reflect only a small percentage of our DNA, and there’s actually more genetic diversity within the African population than between the African population and a European population.
Why is your test most expensive than the ancestry test?
The companies offering these tests largely make their money not from doing the tests, but from selling the genetic information to other companies interested in having access to large genetic databases. Almost 50 percent of the firms that sell you your ancestry information turn around and sell your genetic information to some other company. That’s a big reason you see these test kits advertised as such low prices. They know they will monetize your information and profit heavily from your personal information.
Often these are pharmaceutical companies trying to understand how variations in certain sections of the human genome may be useful in drug development. (Certain drugs may not function as well in a person carrying certain mutations, so the companies want to find the frequency of these mutations in the population.) The vast majority of companies that offer ancestry tests hold onto your sample or sell it. So it’s not just the data, but your actual your saliva, that’s being shopped around.
Can I request my information be provided to GedMatch or another genealogy website after the testing?
Many of the companies have privacy policies that state they can be changed at any time without notifying previous signers. In effect, you need to keep in contact with the company and keep yourself up-to-date on its policy. How many people are going to do that?
There’s also a lot of concern that even though your name is not listed on the database, when the data is sold to somebody, the records can be de-anonymized. It has happened before—people have been able to take genetic information with no name on it and, through other databases, find the name associated with that genetic material. Journey Genetic Testing NEVER sells your data, or uses it for any other purpose. All information is deleted from our company system 30 days after your results are delivered. Nothing is ever provided to any private tor government database.
Discrepancies in ancestry company’s testing process don’t mean that genetic science is a fraud, and that the companies are just making up these numbers. They have more to do with the limitations of the science and some key assumptions companies make when analyzing DNA for ancestry.
What’s not always obvious from these reports is that they’re based on estimates that can vary from company to company, and have built-in sources of error. Your results from one company can change over time as the company signs up more users, and gathers more data. This means that once the information changes, the people that you may be related to may change as well. That may be an unpleasant (or pleasant!) surprise.
To be certain that a relationship you are wondering about is real and exists, you should perform STR testing for the most accurate answers. Just be prepared that someone you are testing against that has been listed as a POSSIBLE relative, may be found through accredited testing to not be related in the way you think they are.