Decoding DNA Discrepancies: Understanding Variations in Results Across Different Genetic Testing Companies

Do you have DNA results from multiple companies and have noticed differences? In this post we will explain why.

People who are passionate about DNA testing often utilize more than one company for testing, or upload their DNA data between the companies. By testing with multiple providers we increase our chances of DNA matches as well as ethnicity estimates.

As soon as we start taking surveys from different companies, it becomes quickly evident that our ethnicity estimates may differ considerably between companies. Some might include whole regions of the world that may not even appear on another set of results.

While we shouldn’t expect our ethnicity estimates to mirror exactly our family tree, it can still be confusing when they don’t appear consistent among companies. How could results on other websites vary so much given our DNA similarities?

Importantly, this information relates only to our ethnicity or ancestry estimation and does not cover DNA matching. Each company calculates our DNA matches similarly so the likelihood that two people share similar DNA should not differ significantly between providers.

Why Your DNA Results Differ Between Companies
There may be many reasons why Ancestry DNA results don’t correspond with 23andMe or Family Tree DNA ones, and here you will find them listed and discussed further below.

Utilize the information presented here to reexamine your DNA test results from each company you used, to see which ones best reflect your family history. Doing this may provide insights into understanding it better.

Every company uses different sample populations for its ethnicity estimates, using various collections of DNA samples collected worldwide to make estimates about customer ethnicity. Each company uses their own method and resources for selecting who will be included in its sample populations.

DNA testing companies provide us with an estimate of our ethnicity or ancestry that can tell us where our ancestors may have lived. While each testing company varies in their process for doing this test, generally speaking by comparing our DNA with people living elsewhere around the world we can learn where our ancestors come from.

However, when given various inputs – in this case different sample populations – as inputs, we are sure to get different outputs; here being DNA ethnicity results.

Some sample populations are larger than others
Large DNA testing companies such as Ancestry DNA and 23andMe can access thousands of DNA samples for estimations purposes; according to their respective websites as of 2022, AncestryDNA used more than 68,000 samples while 23andMe used over 14,000.

These numbers apply only to the general regions we see on our results. Some companies, like Ancestry and MyHeritage, also include features which assign us Genetic Communities or Groups depending on where our samples originate from; these features can often be calculated utilizing more extensive customer databases.

Typically speaking, ethnicity estimates derived using a larger sample population will provide more accurate estimates than ones created based on smaller groupings of people.

Each company has different requirements for their sample populations; all DNA testing companies follow an official policy of only accepting samples from people living in regions with ancestral connections to that part of the world. Since we don’t know exactly how they get included into these samples from one company to the next, some variations could be caused by differences between requirements for inclusion into sample populations and variation between results for various companies.

Each company uses a distinct reference panel As previously explained, our DNA is compared with that of a sample population in order to calculate an estimate. Individual DNA samples do not directly influence this calculation process in any way.

Instead, most companies create what’s called a “reference panel”, comprising DNA samples from various populations to compare with our DNA. If any part of our genome matches one found on one of the reference panels for people from certain regions then an indication will appear on our results that suggests how often yours matched that region’s panel.

Technology behind each company’s reference panels is where things become particularly challenging. Companies want to achieve accurate and precise results and so try different strategies for estimating ancestry.

Technology used to develop reference panels varies greatly across companies, while overall processes will likely have similarities. We know that each company has a proprietary process for developing its reference panel to calculate ethnicity and ancestry. Some are very open about their methods; you may even be able to read published papers detailing them easily enough for an average person.

Read up on Ancestry’s ethnicity estimate process in their Ethnicity White Paper and 23andMe’s Ancestry Composition algorithm process in their white paper (link opens PDF download).

Every DNA testing company defines world regions differently. One common factor for this discrepancy between companies is that different regions have various names or are defined according to historical vs modern borders; we might see multiple areas combined under one region on one DNA testing website while separated out into individual ones roughly correlating with modern country borders on another site.

Ancestry DNA provides two different names for the same region: on 23andMe it’s currently called “French & German Europe,” while AncestryDNA categorizes Germany and the Netherlands under their “Germanic Europe” region.

Family Tree DNA’s map depicts part of the Netherlands under England, Wales and Scotland while Germany falls under “Central Europe.”

An individual of German or Dutch descent might initially misinterpret results from these three companies as dissimilar, but in reality their regions define differently and should produce similar results for someone with German or Dutch ancestry.

Some testing companies don’t report small percentages
Some testing companies have policies against reporting very small percentages (usually less than 1%) which match specific regions – known as trace regions.

Small percentages could indicate either small errors, or distant ancestry that might otherwise remain unknown to us. As a DNA tester myself, I find these small regions especially fascinating as they could reveal something about our ancestors that would otherwise remain hidden to us.

23andMe and MyHeritage are two DNA testing companies that reveal extremely minute percentages on their results: MyHeritage shows less than 1% matching regions; while 23andMe can detect those matching.2% or less!

Hopefully this post has shed some light on why your DNA results differ depending on which company tests them. As now knows it is perfectly normal and does not necessarily indicate one company’s results as being more accurate or inaccurate than others.

If you have any inquiries or observations based on what was written in this post, or would like to share your results based on what has been read here, I invite you to participate in the dialogue below. I look forward to having our conversation!

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