Is It Possible To Be 100% Of One Ethnicity In Your Ancestry Test Results?

It is easier than ever to find out your ancestry through the use of at-home genetic testing kits. The New York Times explains that these kits are super easy to use — all you need to do is spit into a tube or swab the inside of your cheek while following a simple set of instructions and then mail the kit back to the company to await the results outlining your heritage.

After analyzing your unique DNA, the company will compare the results to population data from various places around the world to determine your ethnicity breakdown, according to Ancestry. In the report, you'll see an approximate percentage of each ethnicity broken down by modern-day countries and regions of the world. Additionally, you can discover long-lost relatives who have also submitted their DNA through the company, allowing you to greatly expand your understanding of your family tree. 23andMe takes things a step further by also providing you with a personalized health report that tells you diseases for which you have a genetic predisposition.

One of the fun parts of completing an ancestry kit is discovering the various regions that your ancestors come from, especially if the information you have about your own background is limited. After receiving the results, most people will see an ethnicity breakdown from multiple regions around the world, but you may be wondering if it's ever possible to find out that you are 100% of just one ethnicity. Here's what we know.

Being just one ethnicity is technically possible

In a nutshell, it's definitely not unheard of for someone to receive their ancestry test results and discover that they are 100% of one ethnicity, explains Who Are You Made Of? This happens when an individual's ancestors stayed in just one region of the world for many generations, especially if there was little contact with outside communities.

Even though it's possible to be 100% of one ethnicity, this is not a common phenomenon due to the nature of humans to migrate and connect with groups of people outside of their own, which leads to the mixing of DNA. In fact, when television host Conan O'Brien discovered that his ethnicity is 100% Irish, his doctor was shocked, as per Irish Central. The doctor told O'Brien, "I've never, ever, ever had a DNA result like this before and I've been doing this for 10 years," adding, "I've been doing this a lot, I've seen 93.5 [percent], I've seen 96.1, I've seen 97. No one is 100 percent Irish." Essentially, the doctor chalked up O'Brien's test results to inbreeding.

It's worth noting that the technology used to determine ethnicity is constantly improving and becoming more sensitive, especially as more and more people submit their DNA for testing, explains Family Tree. At the end of the day, these companies are providing a general estimate rather than unwavering facts.