Ethnicity estimates are estimations of an individual’s ethnic background based on an analysis of that person’s DNA. They are commonly given as part of the DNA results received when taking a commercial DNA test, such as the MyHeritage DNA test.
For thousands of years, humans remained in the area where they were born and had children with people who also lived nearby. As genetic mutations occurred slowly over time, people in different geographic regions acquired some unique differences in their DNA.
In addition, people living in each region often acquired shared characteristics such as culture, religion, or language, which we now refer to as an ethnic group. As a result, geography, ethnicity, and DNA became linked in many regions of the world. And scientists have identified many genetic variations common to each ethnic group.
Based on published research and/or first-hand testing, each DNA testing company has developed a set of reference populations for different ethnicities. MyHeritage, for example, has developed a model with 42 such ethnicities.
As part of an autosomal DNA test, the testing company will compare your variants to those of their reference populations. Based on how similar your DNA is to that of those groups, you receive an ethnicity estimate that breaks down your ethnicity into percentages such as this.
What you can learn from an Ethnicity Estimate
In years past, many people would forget or deliberately hide their ethnic origins. Today, there is much more interest in discovering our ethnic roots. We want to know these things, and we want our children to know. Yet many people still know little or nothing about the ethnic origins of their ancestors.
Adoptees and donor-conceived individuals are obvious examples. Yet many people worldwide, including Americans, have not traced their family tree far enough to identify the origins of their immigrant ancestors.
Even if you think you know your ethnicity, DNA ethnicity estimates can help you confirm known ethnic origins. Furthermore, shared ethnicity results can sometimes provide additional clues about how you may be related to a given DNA match.
In any case, it can be exciting to finally know something about one’s ethnic origins.
How Accurate Are Ethnicity Estimates?
The science of estimating ethnicity from DNA is new and evolving. The accuracy of these reports is improving over time. But they are still estimates and should not be considered scientific facts.
While many DNA testers find that their ethnicity estimates reflect their known heritage accurately, others may find their ethnicity results confusing, unexpected, or even shocking.
The ethnicity estimates may not be consistent with their family tree. And some people test with more than one company and get different results. Even if siblings take the same test, they may be surprised to see different ethnicities.
Let’s review some of the reasons why ethnicity estimates can be so different from what people expect.
Random Inheritance
Random inheritance example
One big reason is the issue of random inheritance. Yes, we get 50% of our DNA from our mother. But which 50% we get is random. It's the same thing for our father's DNA.
As a result of this randomness, we can inherit significantly different amounts of DNA from each grandparent. A perfect split of 25% each is highly unlikely.
This random inheritance also explains why siblings will see different ethnicity results. Each conception is a unique event with its own random selection of each parent's DNA. Unless you have an identical twin, each brother or sister will only share about half of your DNA, often showing a different mix of ethnicities.
Migration and mixing
Viking expansion map
In more recent times, people began to move around more and mate with people from outside their traditional ethnic group. The Vikings are a great example, as this map shows their voyages going way back into the 700s and 800s. They even ventured into the Mediterranean and up some of the rivers in Eastern Europe and Russia.
Just like modern sailors, Viking men often left their DNA behind in the local population. Plus, many of them chose to create settlements in areas that are now part of the United Kingdom and France. For more than a thousand years, a lot of Viking DNA has been mixed with other ethnicities in such areas
There are other examples: France and Germany share a single land mass with no natural barriers to impede migration. Even in modern times, the border between those two countries has changed numerous times. Italy and the Middle East are both on the Mediterranean Sea, and traffic between the two regions has been continuous since before the Roman Empire.
In modern times we have national borders between countries. But nationality and genetic ethnicity are not the same things.
Why Ethnicity Estimates vary by company
If you have tested with more than one DNA testing company, you have surely noticed that your ethnicity reports can vary… often by quite a lot. First, the challenges and limitations discussed above apply to every DNA testing company. Nobody has a magic bullet to get around these issues.
Now we add in the fact that each company approaches the estimation of ethnicity in its own unique way. Here are four major differences.
The four major differences between Ethnicity EstimatesGenetic genealogy tests do not test 100% of our DNA. Each testing company uses a customized chip that samples our DNA from somewhat different locations.
Companies use different reference populations with vastly different numbers.
Each company has a unique, proprietary algorithm for comparing our DNA with their reference populations.
Finally, each testing company defines different regional groupings and gives them inconsistent names.
Ethnicity estimates are based on something called “admixture” that reaches back much farther in time than your recent immigrant ancestors… maybe 500 years or so. In a massive effort to provide finer geographic backgrounds, MyHeritage research has also identified 2,114 Genetic Groups.
Members of a group share geographic origins in their family trees but may have multiple ethnicities. For Americans, these can sometimes pinpoint more recent migrations within the US.
Genetic Groups are assigned with varying levels of confidence. A slider lets you select fewer Genetic Groups with a higher confidence level or more Genetic Groups with a lower confidence level.
In the world of genetic genealogy, ethnicity estimates are still a secondary benefit of DNA testing. They're certainly interesting and something to talk about or debate. And in some cases, they may even provide useful clues.
Yet the primary benefit of DNA testing is your list of genetic matches. That's the information most likely to expand and confirm your family tree and introduce you to previously unknown relatives.
