How to Analyze Your Results: DNA Matches

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You got your DNA results back, and you’ve taken a look through your DNA matches.  Maybe you recognize some of the names from the top matches, and everything seems to make sense.

There is more to see, however.  In this post, I’ll teach you how to analyze your DNA results using your DNA match list.

It’s probably fair to say that most people first do their DNA test to get their ethnicity estimates.  Additionally, many people don’t know that they will get a DNA match list, or really understand what that means.

It can be overwhelming to look at a list of people who are definitely genetically related to you in some way, yet not know who those people are.  Yet, spending some time analyzing your DNA match list can help you:

• Verify that your family tree is correct
• Provide evidence that your family tree might have a few errors (many do!)
• Help adoptees and others locate their biological parents and other close relatives
• Assist you in better understanding your ethnicity estimate

In my own DNA match list, I have found close cousins who were previously unknown to me, proof of who my great-great grandparents were on one of my mother’s lines of the family, as well as evidence of the migrations my ancestors and their descendants took around the world as they established their families in other countries – and much, much more.

This is the second post in a two-post series.  The first, How to Analyze Your DNA Results: Focus on Ethnicity Estimate, is an in-depth explanation of strategies you can use to learn the most from your ethnicity estimate.

Below, I’ll discuss some strategies that you can use to learn to analyze your DNA results – with a focus on your DNA match list.  This post is written for people who tested with any of the major testing companies, but occasionally I might mention a feature that is available with a specific company in order to demonstrate a technique.

How to analyze your DNA match list

One of the most important bits of information that you need to have when you first open up your DNA match list is that your DNA testing company will estimate your relationship with each match, but you won’t know exactly how you are related until you really start digging into your family tree, using your amount of shared DNA as a guide.

Your testing company uses the amount of shared DNA to make an estimate, since there are ranges of shared DNA typically seen for each relationship type.

The only relationship that is almost always estimated correctly is the parent/child relationship – so if you see this on your list, it is just about certain that this person is a parent or child to you.  Situations involving identical twins are just about the only exception to this “rule”.

Step One:  Examine your first five DNA matches

The first thing that you will want to do when you open your DNA match list it to examine the first five or so DNA matches.  Generally speaking, the people who are at the top of your DNA match list are the most closely related to you, since our match lists are usually sorted in a way that shows the people who share the most DNA with us at the top of the list.

We share most DNA with our closest relatives.  As our relationships grow more distant, so does the amount of DNA that we share.

For example, you will share about 50% of your DNA with either of your parents, but only about 3% with a second cousin.  I used percentages for this example, but typically genetic genealogists (like me and you!) will use the term “centimorgans” to discuss the amount of DNA that two people share.  We usually abbreviate the word centimorgan like this: cM.

As you examine your first five DNA matches, you will want to look for the following information on each match, even if you already know how the match is related to you:

• Does your match have a family tree posted on the website?  Viewing their tree can help you determine your common ancestor, which can tell you how you are related
• Amount of shared DNA (cMs) that you have with the match (read how to view this info on Ancestry)
• Who are the matches that you share in common with each match?  Who do you not share in common?
• Is the number of centimorgans within the expected range of shared DNA for your relationship distance?
• Which ethnicities do you share in common with your match?  This can help you figure out which lines of your family a particular ethnicity came from.

Here are some other questions to ask yourself as you move through those first several matches:

• Is there someone that you were expecting to see that you don’t see?  Keep in mind that we share DNA with all of our close relatives, but with more distant relationships, there is a possibility of no genetic relationship (even if there is a verified genealogical relationship).  For example, there is a 10% chance that you won’t share DNA with a third cousin, though it is impossible not to share DNA with relationships closer than a third cousin.
• Do you have a match within these first five matches that you don’t recognize?  If so, how much DNA do you share with them?  (See this post for a guide about shared cMs and relationship estimates)

Step Two:  Begin to incorporate your DNA matches into your family tree

What’s this I hear?  You don’t have a family tree?  No worries!  Most people who do a DNA test don’t have a family tree yet.   I typically build my family trees on Ancestry, since it is really easy, you can connect your tree with your DNA results, you have access to tons of documents, and you can even export your tree to another site if you want to.

With that said, there are lots of great family tree websites out there, and you should be fine no matter which one you choose.

The exercise that I recommended in the first step was primarily to teach you how to think about each individual match, and to know what to look for – and of course, to help you spot anything major that you need to know before you get started building your tree.

Ideally, you have the time and the inclination to go through a great deal of your DNA matches – pace yourself and only do a few per week when you are just getting started.

What do I mean about incorporating your DNA matches into your tree?  Once you have the past few generations of ancestors added to your tree, you can go ahead and add your DNA matches.

For example, if you have a second cousin on your DNA match list who has a family tree with an identifiable common ancestor (someone you recognize), you can add your great-grandparents’ other child (who is the ancestor of your match), along with their child, and your DNA match to your tree.  While you are doing this, you can add other people from their tree.

This strategy means that you will “build your tree wide”, adding in living relatives and their ancestors as you move though your DNA match list.  This is an excellent way to save lots of time in the future, especially as you start to go through some of your more distant matches.

Step Three:  How do your DNA matches align with your ethnicity estimate?

You should expect to see DNA matches that share your major ethnicity percentages with you.  Many of us (I’m including myself!) are very interested in our “trace ethnicities”, or larger ethnicity regions that are unexpected.  One way to tell whether or not you have a recent ancestor from a particular region is by closely examining your DNA matches.

For example, let’s take my own Eastern European percentage of 43%.  This could mean that one of my parents is about 90% Eastern European, that each parent is about 50% eastern European, or that one parent has a lot of Eastern European and I just happened to inherit a good deal of it.

Even if I didn’t know anything about my family tree, I could determine which scenario is likely to be true by looking at my DNA match list and their posted family trees.  In the case of a recent Eastern European ancestor, I would be looking for many top matches with parents born in an Eastern European country.

I don’t see any close matches like this on my list, though.  I do see that many of my matches have Eastern European as an ethnicity, but they also have lots of other ethnicity regions.  When I look at their family trees, I see that some of them have great-grandparents, and great-great grandparents born in Germany, Poland, Czechoslovakia, Austria and Russia.

This means that I inherited my Eastern European DNA from several great-great grandparents, most likely (which happens to be true).

On my Ancestry DNA results, I showed 1% European Jewish.  In a perfect world, this could mean that I inherited this ethnicity from an ancestor 5-7 generations ago.

The problem is that I don’t have any DNA matches have European Jewish as their primary ethnicity, leading me to believe that I probably inherited this ethnicity from an ancestor further back than 5-7 generations, or even from a few different ancestors (meaning that several of my ancestors had small amounts of European Jewish).

Once you got through the first several pages of your DNA matches (and their trees and ethnicity estimates), you’ll get a good idea as to how far back a particular DNA ethnicity ancestor might be, and whether or not you should spend much time trying to track down a particular ancestor.

Much of the time, we inherit an ethnicity from more than one ancestor – making it difficult to pinpoint exactly where it entered our lineage.

Step Four:   Do you want more DNA matches?  I do!

If you don’t have as many DNA matches that you thought you would, you might be interested to know that Family Tree DNA and My Heritage DNA accept free DNA transfers.  You can read this post about other places that accept DNA uploads:

Step Five:  Consider using advanced tools to analyze your DNA matches

I am a huge fan of Gedmatch and DNA Painter, which are both free tools that you can use to analyze your DNA data using your DNA matches.  Gedmatch also offers additional tools that can be used to more closely examine your ethnicity.

If you are new to DNA testing and you just got your results back, keep these tools/sites in mind for when you feel ready to learn about the intricacies of what your DNA can reveal to you.

With that said, Gedmatch offers some relatively easy to understand tools, and more DNA matches – so I would definitely consider uploading your DNA to site so that when you are ready to use a tool, you have everything there at your fingertips.

Conclusion

I hope that this post has given you some ideas as to how to really understand your DNA matches, and how you can use those matches in tandem with other information to build your family tree and better understand your ethnicity estimate.

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