What You Will and Will Not Learn by Taking a DNA Test for Ancestry

As more and more people choose to test their DNA in an attempt to better understand their family’s past, a lot of questions are popping up about what a genetic test can and can not tell you about your ancestry.

In this article we’ll go over some things you will learn by testing yourself, or your family members, and some things you won’t be able to uncover unless you combine your results with traditional genealogy research.

Please know that we have linked to a variety of DNA companies in this article and may receive a commission on any sales made through these links. These commissions support our work. 

Perhaps you’ve already tested your DNA with one of the current testing companies and are waiting on the results, or maybe you’re simply weighing the pros and cons of buying a test. Either way, it’s important to know what to expect before your results come in.

But before we dive into what you can and cannot learn, let’s take a moment to understand how DNA testing for ancestry works. After you spit in that little tube, or scrape the side of your cheek, and mail it off to your chosen testing company your sample is analyzed in two ways and you will receive two types of results.

Ethnicity or Ancestry Report – This is the report most people test to get. Here, your DNA is compared to thousands of reference samples from various regions around the world to see which populations are reflected in your genetic code.

You will be given, as part of your results, a breakdown of populations that you match. Depending on how refined the regions are from the company you tested with (they are getting more specific with every update) you might see something as broad as Scandinavia or as specific as Sweden. Your ancestry report will likely be a mix of many populations.

Cousin or Relative Matching – As a second part of your report you will also be matched against other people who have tested (some companies like LivingDNA do not currently offer this). In this case the testing company is looking for people who you share a genetic connection with. Most of these connections will be distant, 4th or 5th cousins are common, but some will be closer – 1st, 2nd or 3rd cousins removed to different degrees. Parents, grandparents and siblings who have tested will also be shown.

For this information to be useful you will need to look at the family trees these individuals have uploaded, as well as shared matches and ethnicities, to discover how you can help one another discover shared ancestors.

Unless you are looking for a lost family member this part of your results is, for the most part, only helpful when combined with traditional genealogical research. Companies like MyHeritage and Ancestry have done a good job of providing tools to help with this. You can read more about MyHeritage’s platform here.

Things You Will and Will Not Learn by Taking a DNA Test for Ancestry

You Will Not Learn – Your exact genetic makeup or the exact locations your ancestors came from

Since testing companies are looking at your genetic information (which you inherited from your ancestors in varying amounts) to determine what populations you match around the world, your results will be a reflection of where your ancestors lived at different points in the past.

But humans are all incredibly genetically similar. No matter what part of the world your ancestors resided in, we all came from the same place once and only a very small amount of our genetic information separates us from one another. In addition to this, humans love to move around and intermingle. This means that, from a genetic standpoint, it is incredibly hard to tell the difference between two nearby regions.

Testing companies have developed highly researched sample populations that represent different regions but the science behind this is still developing. The reports testing companies offer are getting more refined (countries in some cases vs whole regions) but they are still far from exact.

For this reason, don’t expect to get a highly specific and unchanging breakdown of where your ancestors come from when you get your results back.

You Will Learn – An estimated breakdown of where your DNA comes from, which are the general regions your ancestors resided in

What you will get in your reports is a mix of percentages from various regions that your genes most closely match. Expect a general, broad picture of your family’s geographic past and connections with various genetically specific ethnic groups.

You can also count on the fact that each testing company will provide you with different results based on their own population samples and calculations. Don’t be shocked if you test with more than one company and end up with a whole new set of populations for each. Siblings may also experience big differences in DNA test results since they inherit different genes from each parent. To see reports for the same person from four of the top testing companies read this article.

You should also know that your results will change over time with each update that comes out. Record your results so that you are ready to compare them when changes are made.

Here is an example of an ethnicity breakdown from AncestryDNA before and after their big Sept 2018 update. Notice how some regions were removed, others were refined into countries and still others changed in percentage.

AncestryDNA Ethnicity Results Before Sept 2018 Update

AncestryDNA Ethnicity Results After Sept 2018 Update

To better understand how to best interpret your ethnicity results please read Why You May Be Reading Your DNA All Wrong.

You Will Not Learn – Which ethnic percentages come from which parent

The DNA tests for ancestry that have become so popular, and that are most useful for genealogical purposes, are autosomal tests. Family Tree DNA, MyHeritage DNA, AncestryDNA, 23andMe and LivingDNA all offer autosomal kits. These tests look at sections of your entire genome across all 23 chromosomes, showing information from both of your parents, their parents, their parents and so on.

They do not, however, separate this data by the individuals who contributed it. Don’t plan to find out whether Dad, specifically, was Italian or Mom Native American. You will need to do further testing and research to break this information down.

You Will Learn – Details that can be used to figure out which side of your tree an ethnicity comes from

While the DNA tests for ancestry can’t tell you exactly who contributed that 6% Italian you see in your percentage breakdown – you can work to figure this out on your own. By interviewing and testing additional family members, using phasing to separate results, studying chromosomes and connecting with your genetic cousins you can start to make sense of and segment your results to better understand your family’s past. But you will need to invest some time.

You may want to sign up for one of our online genealogy courses to help you make sense of DNA for genealogical research.

You Will Not Learn – The names of your ancestors

A surprising number of people believe that if they test their DNA they will be connected with a giant, established family tree that will tell them just who they are related to – or that by testing their DNA they will be able to simply pick out ancestors who match genetically to add to their tree. This is not case.

DNA tests for ancestry do just what is explained above and nothing more. They provide you with a general breakdown of populations that best match your genetic code and show you a list of living people who you share DNA with.

You Will Learn – The names and contact information for living relatives who have also tested, and valuable genetic information that can be put to use in your tree

The information provided by DNA testing can be incredibly valuable to researchers, but you have to know how to use it. A DNA test is not a shortcut to building a family tree, it is a tool.

By gaining insights into the genetic populations that you match, and connecting with relatives that can help you with your research, you will have a leg up with trying to decipher your family history.

To best understand how genetics and genealogy can be combined to help you build a quality family tree please see the genetic articles on this site or read more from the International Society of Genetic Genealogy.

You Will Not Learn – Everything you need to know to determine whether you match a specific ethnic group

Many people take DNA tests in the hopes of discovering whether or not they are Native American or some other ethnic group. Often, this desire comes from a family story and we hope that a test will confirm or deny the tale once and for all.

But the truth is that DNA tests are limited and results are not always clear enough to give a definite answer.

It is important to remember that DNA tests generally only show measurable and fairly accurate results for the last 6-7 generations or less (after this less than 1% of your DNA comes from any given ancestor). You can certainly have recognizable DNA segments further back than that, but they are usually only noticeable upon close examination of chromosomes and are not likely to show up in your ethnicity percentages.

Additionally, you only inherit some DNA from some of your ancestors, so you do not have an equal share of information from all of your forebearers.

For these reasons, you may have an ancestor who was Native American, for instance, but who existed too far back to detect. You simply no longer carry enough of their DNA to be picked up by a test and will need to rely on genealogical research to discover whether your family story is true.

Conversely, if you do end up having Native American DNA, a test will only tell you this is very broad terms. You should not expect be told that you are 5% Cherokee, for instance. Unless you have recent known Native American ancestors you are not likely to find such a significant percentage and, even if you do, you will not be told what nation, tribe or band it comes from. No DNA test is that specific.

Additionally, it should be known that tribal nations do not accept ancestry DNA test results to apply for enrollment. Tribal members have recent, well-documented ancestry and trying to use a DNA test to gain membership is inappropriate at best.

Other small percentages can be confusing as well. You may discover that you show DNA for an unexpected group, like Jewish, or a region, like Southern Asia, even if you have no known ancestors that match these results. These small percentages may be accurate and could reflect hidden ancestry or they may be a confusion of results from other populations.

A DNA test can bring these small percentages to light, but they cannot tell you who contributed this DNA or whether or not what you are seeing represents real ancestry.

You Will Learn – Some of what you need to know to solve family mysteries and uncover hidden ancestors

By testing multiple family members, connecting with genetic cousins and digging deeper into your DNA by utilizing advanced tools on places like GEDmatch you can use the information you gain from these tests to discover more information about your family’s past.

A small amount of DNA you didn’t expect could lead you on a journey to discover a part of your past you didn’t know existed, whereas a lack of expected DNA could be just the catalyst you need to start digging into the records to see what you can find with traditional research.

You Will Not Learn – Your identity

If DNA testing is teaching the world anything, it is that we are all much more greatly mixed than many realized – and our cultural identities don’t always align with what we discover from our genetic code. While many people test in the hopes of solidifying an idea of who they are, they end up discovering that their genetic story is much more complex than they ever could have imagined.

So, if you are hoping to take a DNA test to reinforce your personal, cultural or family identity, you might be in for a surprise. Just remember, our identities are shaped only in part by our genes.

You Will Learn – A valuable part of your biological heritage

Genetic testing is far from perfect, but it will give you a fascinating peek into what makes up your family’s biological past. This information is incredibly valuable to anyone who is interested in understanding their heritage. But a DNA test can only ever show you part of your family’s story – you will have to discover the rest on your own.

For a detailed breakdown of the top four DNA tests for ancestry purposes read our guide to choosing the best one for you.

You might also like to read:

• The 4 Best Places to Upload Your Raw DNA Data
• 4 Things You Should Do With Your DNA Results and 3 You Shouldn’t
• Why You Might Be Reading Your DNA Results All Wrong
• Who Counts as Family in a Family Tree

By Melanie Mayo, Family History Daily Editor

Featured Image: AncestryDNA Ethnicity Report, Oct 2018