How to Find Out Your Ethnicity Percentage

In this article, you will learn about how to use DNA testing to find out your ethnicity percentage.

You take a look at your family tree written out in front of you and you see that one of your ancestors, perhaps a great grandparent, was a full-blood member of the Cherokee tribe. When relating this to people we may say something along the lines of “I’m 1/8^th Cherokee”. In a perfect world, this math is accurate, but in reality, the science of DNA inheritance is not so simple.

DNA Inheritance

The truth of DNA inheritance through generations is not as cut and dried as we might think. We inherit a 50/50 mix of DNA from our parents. This is exact and there is no variation.

When it comes to our grandparents, logic dictates that surely we got 25% of our DNA from each of those 4 people. This is assumed because our parents got a 50/50 combination of their DNA from our grandparents.

Here is where the percentages start to fluctuate, because the DNA we actually receive recombines before we get it, from our parents. So as an example from our father we may get 23% of his father's DNA and 27% of his mother's DNA.

As a result, once we reach our great grandparents we can actually end up getting between 4% to 23% of our DNA from a single great grandparent. This can greatly affect our ethnicity estimates in that although we have a Native American ancestor within living memory it may barely show up at all in our actual DNA.

How the DNA Database Is Created

There are several companies offering DNA Ethnicity estimate tests including Ancestry, 23andMe and MyHeritage. Whichever test you take the process is very similar and it involves a lot of hard work from the companies in question to build their databases.

There are ongoing projects around the globe to collect DNA samples from the people who live in specific regions. Some of these people may be descended from individuals that resided in roughly the same area hundreds of thousands of years before.

In an ideal world, we would love to have the DNA from the original people that settled in a particular area. This, however, is not really possible even if we were to discover graves of people who had lived and died in an area 1000 years ago. The trouble being that DNA degrades over time and getting a good sample is very rare.

This is why we rely on taking a large sample of as many people as possible who live in these regions today in order to build a database. It is against these databases that our DNA is tested.

Accuracy of the DNA Test

Given that the database is made up of modern-day inhabitants of a region, obviously, there is some room for error. We have to bear in mind that populations have shifted over time and in some cases, mass emigration or immigration can make an impactful change in an area.

Regardless of this, however, if an area is sampled extensively there is a decent chance that people whose family goes back many generations in the same area will be recorded. In terms of expected accuracy in ethnicity tests, it is thought that they can give a fairly accurate view of your ethnicity going back 300 to 500 years in the past.

What the Ethnicity Percentages Mean

Depending on the company you test with there are slight variations but, in general, the same principals will apply. Hundreds of thousands of markers are checked in our DNA samples and compared to numerous populations around the world.

What is being checked in these comparisons is the probability that the markers in our DNA are found in those local populations. The more frequently those markers appear in a population sample the higher the likelihood that our ancestors may have lived in that region.

Obviously, this process is performed with all the markers that the company has checked in our DNA. Complex algorithms have been created by these companies that analyze all of the potential matches and produce the estimates.

As science improves and more and more people are tested the process becomes more refined and accurate. Someone who tested 10 years ago and was given 94% British as their main estimate may find today that the results have refined it down to 44% Welsh, 13% Irish and various other miscellaneous Northern European countries.

How to Make DNA Results More Accurate

These tests are rightly called ethnicity estimates because as mentioned the nature of DNA inheritance becomes hit and miss after a few generations. We could have a direct ancestor from West Africa but because they were a great great great grandparent we never received any of their DNA.

So if we can be missing DNA from ancestors how can we possibly get an accurate ethnicity estimate? Retesting is out of the question because, obviously, our DNA doesn’t change. We may, however, have potential DNA samples similar to our own but different enough to catch the missing puzzle pieces.

There are people we share a lot of DNA with - grandparents, parents, siblings, aunts and uncles. These people descend from the same ancestors as we do. It is possible that DNA from that West African ancestor is hidden in one of these blood relatives.

Asking close blood relatives to take the tests as well will give you several different profiles to compare against each other. If your grandparents are available they are a great resource as their DNA is two generations closer to your ancestors than your own is.

It should be mentioned that cousins may also be helpful in increasing the accuracy. Although it should be remembered that one of their parents is likely not a blood relative to you or your close family.

How We Can Determine Our Own Ethnicity Estimate

With solid genealogical research going back several generations we could conceivably get a reasonable idea of who we should be genetically. If we based this on perfect generational DNA inheritance it would be accurate potentially on paper if not actually in our genes.

It is likely a good idea though to see what our DNA says and this is best performed by going to one of the professional companies. There is always the possibility that our DNA may uncover a lie in the paperwork.

Neil Edwards

Genealogist and family-tree research specialist

Neil was born in Shropshire, England surrounded by centuries of living history. His interest in the past has been a lifelong passion leading to undergraduate degrees in both Economic History & Geography and History & Politics.

This interest in history quickly translated to family history when he moved to the U.S. in 2010. It was here that he began working on his own family tree as well as that of his American wife. That research allowed him to gain a wealth of experience working with both U.S. and European genealogical documents and studying their best uses in researching family history.

Following 9 years of honing his genealogical research skills, Neil was proud to have earned a certificate in Genealogical Research from Boston University in late 2019. Neil also took part in the research process for a Duke University study into the families of 19th Century UK Members of Parliament.

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