Short version: The accurate way to read an ethnicity estimate is, “Ancestry is 38% sure I have ancestors from Nigeria”, not “I am 23% Nigerian”. Replace the company and ethnicity appropriately.
I received my AncestryDNA results several years ago, and after breathing a sigh of relief upon looking at the DNA matching, I looked at the ethnicity results. I immediately knew something was wrong, but I accepted the results anyway. As I read them, I thought, “I am 23% Nigerian, 12% European, etc.”
Looking at the list, while my Asian DNA was on there, I knew the European estimate was wrong. Half of my great-grandmothers were so fair they could pass for white. The family story about having a Native American great-grandmother died that day. My results inspired me to learn more about my family DNA history.
Some time later, I received notification that my ethnicity results changed. They were more accurate than ever!
Wait…what?
What an Ethnicity Estimate Really Means
Our DNA does not have a race or ethnicity gene. Race is a social construct, not a biological one. The proper way to read an ethnicity estimate is, “Ancestry is 38% sure I have ancestors from Nigeria, 18% sure I have ancestors from Europe, etc.”.
See the difference?
The companies providing ethnicity estimates use a reference panel of people they tested that, allegedly, have a long history living in a particular area. Then, they compare your DNA with those of the reference panel. Percentages, based on algorithms, are calculated based on the closest matching populations.
You cannot DNA match a population unless it is represented in their reference panel. The estimate can also show the ethnicity of where the ancestry originated from, not where they resided.
How Accurate are Ethnicity Estimates?
When a company matches your DNA to a location, it is reasonably accurate you had ancestors from that area. The estimated numbers are not accurate. Since ethnicity is not in our DNA, the estimate is only as accurate as the reference panel.
The issue with ethnicity estimates is that they can lead people to believe that an ethnicity is missing from their results when it might not be. In my opinion, companies that offer these tests do not do enough to correct this perception. They will often explain that a person receives 50% of their DNA from each parent, and therefore also misses out on the other 50% of their DNA that is not passed down. For example, if a person’s parents or grandparents had Native American ancestry, it is possible that this ancestry was not passed down to them. However, what these companies do not say enough is that their reference panel for determining ethnicity is often incomplete. This can lead to inaccurate or incomplete results.
Ancestry is Updating their Reference Panel…again
I noticed Ancestry is updating their reference panel in August 2022. They are adding 8 new regions.
