27 June 2023

Do Your DNA Ethnicity Results Make No Sense?

Two people contacted me lately about an odd ethnicity in their DNA results. The three of us share ancestry in my grandfather's hometown, so they wondered if I'm seeing what they're seeing. I'm not, but I have a few curious results, too.

That's why I was excited to join another Diahan Southard webinar titled "DNA Ethnicity Estimates: How to Actually Use Them!" One of the most important things I learned was, basically:

If your results show less than 5% of an unexpected ethnicity, it's probably not reliable.

Here's how to get a better idea of its reliability. I'll use AncestryDNA as an example, but most DNA websites have similar tools.

  • Click on the unexpected ethnicity in your results. I chose my mother's unexpected 2% Portugal.
  • This opens a panel that tells you a bit more, such as "Primarily located in Portugal; Also found in Spain." Their map tells me this ethnicity may cover Spain's whole west side.
  • Now look at your percentage. In this case, it says 2% Portugal, but beneath that it says it "can range from 0% to 5%." That's right. It's as low as 0%.

I've documented my mother's ancestors in a small area of Southern Italy going back to the very early 1700s. Could someone have come from Spain or Portugal before that? Sure. And since FamilytreeDNA tells me I have 6% Iberian Peninsula, there probably is some ancient connection.

But that doesn't matter to my family tree, does it? I'll never make a documented connection to a centuries-old ancestor from Spain or Portugal.

My father's results have a laughable result of less than 1% Norway. Less than 1%! When I click it I see that his estimate is 0%, but it can range from 0% to 1%. That sounds like we can disregard it, don't you think? He has no Norway on MyHeritage.

In fact, all Mom and Dad's ethnicities but Southern Italy and Northern Italy could be as low as 0%. The same is true for me, with one exception. Even my Northern Italy could be as low as 0%.

Dig deeper into tiny, unexpected ethnicity results.
Dig deeper into tiny, unexpected ethnicity results.

AncestryDNA says the DNA samples they test you against "divide the world into 84 overlapping regions and groups." I can see that what they're calling Southern Italy and Northern Italy overlap close to the area we come from. Taken together, this makes me confident we are Southern Italy, going back at least as far as the paper records go.

But, if you *don't* know where all your people came from for the last 300+ years, pay attention to your unexpected results. They may be the clue you need.

A Range of Ethnicity Results

Why would AncestryDNA tell me my Northern Italy is 8% but it may range from 0 to 39%? This is from their website:

"We compare your DNA to a reference panel made up of DNA from groups of people who have deep roots in one region. We look at 1,001 sections of your DNA and assign each section to the ethnicity region it looks most like."

They look at 1,001 different sections of your DNA! Your DNA isn't one homogeneous strand. Each section can show a different percentage of an ethnicity. That means that my 1,001 test results for Northern Italian DNA ranged from none to a high of 39%. The average of all the tests was 8%.

Where the Action Is

For a long time my AncestryDNA results didn't show any of what they call Communities. Now I have three that either touch or overlap one another. And they are 100% true to my documented, massive family tree.

From Mom's side:

  • Avellino & Southwest Foggia Provinces
  • South Benevento & North Avellino Provinces

From Dad's side:

  • Campobasso & East Isernia Provinces

I can prove that our documented ancestors are from the Benevento & Avellino Provinces. AncestryDNA bases these communities on the family trees of DNA matches. And they're very accurate, according to DNA expert Diahan Southard.

My husband's AncestryDNA test has a disappointingly low number of DNA matches. But I love his community! It fits everything we know about his ancestors: "Hiroshima, Yamaguchi, Fukuoka, Olta & Kumamoto." Here's what Ancestry says about how they determined this as his community:

"You, and all the members of this community, are linked through shared ancestors. You probably have family who lived in this area for years—and maybe still do."

I'll leave you with another great tip from Southard. Say you're trying to trace a close ancestor—a 2nd great grandparent or closer. And you have no idea where on earth they came from.

Do you have a DNA ethnicity that doesn't match what you know about your ancestry? Check your mystery DNA matches' ethnicities. (On AncestryDNA, Ethnicity is a tab, like Shared Matches.) Do any of these matches have a decent amount of that one unexpected ethnicity? Check their family tree and Shared Matches to see if their information that can help you.

Also, take a look at which ethnicities you actually share with your decent DNA matches. If they don't have small amounts of something you have, then that ethnicity has no bearing on your connection.

What's the bottom line with all these ethnicities?

  • Be sure to check out the range of percentages. If it says it's as low as zero, it's may be too little to matter.
  • If the average is below 5%, don't expect to find a documented ancestor from that part of the world.
  • Check to see how your DNA matches' ethnic percentages compare to yours.

If some of your DNA ethnicity results simply don't make sense, give them a closer look. If you can see they're not worth pursuing, don't worry about them.

Here's a good way to look at it in mathematical terms:

  • Each of your parents gave you 50% of your DNA.
  • Each of your grandparents gave you 25% of your DNA.
  • Each of your great grandparents gave you 12½% of your DNA.
  • Each of your 2nd great grandparents gave you 6¼% of your DNA.
A tiny percentage is either a statistical error or a very distant ancestor.
A tiny percentage is either a statistical error or a very distant ancestor.

I know exactly where all my 3rd great grandparents came from, as well as 55 of my 64 4th great grandparents. It's crazy to imagine that one of my nine missing 4th great grandparents walked to Southern Italy from Norway or Portugal! That gives me the confidence to ignore those trace ethnicities.

How about you?

Don't lose any sleep over tiny, unexpected DNA ethnicities.
Don't lose any sleep over tiny, unexpected DNA ethnicities.


  1. I have one of those 100% husbands also. You would think that would make things easy, but they each had 2-3 surnames they used.

  2. Interesting article however I think my small percentage is different. I was born in England. My ancestors were mainly Irish, some Scottish and some English. I had figured I might be close to one eighth English according to my research. However I have, according to Ancestry, only 2% English. My great great grandparents were grandfather English and grandmother half English and half Scottish. In my case the two percent English is definitely relevant. It is due to the random chances of what we inherit from each parent. Each of my parents would have been (very likely) each 75 % Irish but I have inherited 85% Irish. I got a lot of my mum's Irish and very little English. Dad had only Irish and Scottish. My mother's sister has 6% Irish. Her mother should have been about 37% English but this somehow hasn't been passed down (perhaps she inherited more Scottish than seemed likely). There may be more Scottish than we know of (it being a small island).
    I just wanted to point out that my 2% English is actually relevant. So very small percentages can be an indication of actual ancestry.

    1. You've got a small geographical footprint on your side, so your small percentages are relevant. The problem is when many of us have low percentages from extremely distant lands. I know that my family's small percentages from far, far away are either untraceable through records, or an error.

  3. PS - re very small percentages. The original poster thought that his great great grandparents would not have walked to Italy from Portugal. True I am sure but if you have any ancestors who lived near a port then that can account for some of the discrepancies. Our ancestors aren't always what the paper trail says. Many of my relatives have small percentages of Norwegian too. We will not find any paper trail to that but, in an island like Britain, the Vikings had quite a presence a thousand years ago. It wasn't the odd person. There were large settlements and they did settle. Eventually they would have become part of the native population. Could any of this have been true, in very small part, in Italy or other European countries?

    1. If they had left a port and had reason to travel, they made a mistake going to a remote and impoverished part of Italy! My ancestral geography plays a big part in my logic.