The topic of DNA ancestry tests tends to be rather controversial among a lot of marginalized ethnic groups these days, and for good reason. We are seeing more and more people claiming to be descended from “unique” bloodlines based on the results of DNA ancestry tests.
However, most geneticists argue that DNA ancestry tests aren’t as accurate as the companies who offer them make it seem. In fact, some scientists have begun referring to such tests as “recreational genetics” due to their lack of accuracy and the assumptions such tests make about human populations, ethnicity, and race.
There are certainly things a DNA ancestry test can tell you, but there are many things it cannot.
What can a DNA ancestry test tell you?
Well, it can tell you with whom you share DNA. DNA ancestry tests have allowed many people to discover distant relatives, or have been used to find biological parents. DNA tests can certainly do those things, but there is much more that DNA cannot tell us.
So, what is it that a DNA ancestry test cannot tell you..
It can’t tell you your ethnicity. The way most DNA ancestry tests work is that they compare the genetic markers in your DNA with the genetic markers found in other people’s DNA, and they make an assumption about your heritage based on similar genetic markers.
That sounds pretty reliable on the surface, but it completely ignores how ethnicity is defined, and even how human genetics really work.
When two people reproduce, only a portion of each person’s DNA is passed on to the offspring, and which bits and pieces of genetic code you inherent from your parents’ is completely random. So, unless you are an identical twin, you don’t even share the same genetic code with your siblings.
This means that a genetic marker common to a certain ethnicity might be passed on to your siblings, but not to you. This means that even if you have children with someone of the same ethnic background, those children have a chance of not having that common genetic marker, but that obviously doesn’t change their ethnic heritage, does it?
It can’t tell you your race. In the same way that DNA can’t determine ethnicity, it also can’t determine your race. You might get a DNA ancestry test that reveals you share 40% of your DNA with a certain racial group, which is confusing to you because there is no evidence in your family of any recent ancestor belonging to that racial group.
DNA ancestry tests rely heavily on comparisons. They compare your DNA to whatever DNA already exists in their database, which means that companies offering DNA ancestry tests are pooling DNA from a very small portion of the human population. There is an over-representation of DNA samples from people of White, Western European ancestry, and people of African American ancestry. This heavily skews the databases these companies have, and is why different testing companies will likely give you different test results.
You might be entirely of East Asian heritage, but your DNA ancestry test results say you share 28% of your ancestry with Sub-Saharan Africans. That’s because somewhere deep in your ancestry, someone passed along a genetic marker that is common in Sub-Saharan Africans and you just happened to inherit that genetic marker. It doesn’t make you African. It doesn’t even make your ancestors African. It simply means that you share a piece of your genetic code with a lot of people from Sub-Saharan Africa.
That’s perhaps the biggest flaw in DNA ancestry tests; they can only tell you that you share DNA markers that are common to a certain group of people. They cannot definitively say you descend from a certain group of people.
It can’t tell you geographical ancestry. Humans have been migrating across the planet since we were, well.. humans. Even though many groups of people settled down and created agricultural societies, languages, and homelands, human migration has never once stopped. What are the implications of that in DNA ancestry tests, though?
Unfortunately, some DNA ancestry tests conflate geographical ancestry with ethnic ancestry, and as we already discussed, DNA ancestry tests can’t even accurately tell you ethnic ancestry.
This is common among the ancestry tests of some Eastern Europeans, some of whom might show genetic markers common in the Eurasian Steppe. Your DNA ancestry test might tell you that you are 27% Kazakh, but that doesn’t mean your grandparent was from Kazakhstan. It means that you share 27% of your DNA with the majority of the Kazakh people, who share a common ancestry with other Eurasian peoples who invaded Europe around 400 AD. So, even if you really did have Eurasian ancestry, and you might, it is likely very distantly removed, as in from 400 or 500 AD.
It can’t tell you that you were related X, Y, or Z famous person.. at least not most of the time. The problem with DNA ancestry tests claiming you were related to some historical figure of the not so recent past is that in order to actually prove that relationship, the testing company would have to have a sample of DNA from that person. Most of the time they don’t; they make claims based on.. you guessed it.. shared genetic markers of people claiming that lineage.
It can’t tell you your identity. Identities, particularly national, ethnic, and racial identities are not arbitrary; not in either sense of that word. Such identities not only change because people move, intermarry, and borders change. However, they also cannot simply be decided on a whim because there are definitely socially constructed parameters determining ethnic, racial, and national belonging.
You could get a DNA ancestry test and the results might say you share 80% of your DNA with the population of France, but no one in your recent family history is French, there is not even any evidence of anyone in your recent family history having been French, and you’ve never been to France. That doesn’t suddenly mean that you are French, and should start eating baguettes and saying, “Sacré bleu!” It means you inherited some genetic markers that are common among French people.
Genetics are complicated. They are much more complicated than most of these DNA ancestry testing companies would want you to know.
While DNA ancestry tests can be a great tool in corroborating known family history, they should never be taken at face value because genetics are.. complicated. They can’t tell you most of the things these companies are claiming they can because our knowledge of genetic ancestry and our DNA testing abilities are simply not advanced enough to do so.
If you look hard enough for some unique or interesting ancestry, you will find it simply because you want to, but that doesn’t make it true. DNA ancestry tests have only amplified that desire while creating a false positive history for many people.. and this has become a problem particularly for people of small, marginalized, ethnic communities living in Europe, the US, and Canada where most of these tests are done.
No DNA ancestry test is going to change who you are, nor will it change your family history. Most importantly, however, no DNA ancestry test is completely accurate.