DNA Matches: What You Can Do with All Your Genetic 4th Cousins

(Update 2020) When genealogists take an ancestry DNA test, they are looking for more than just their ethnicity results. They are also very interested in receiving information on other people who have tested who closely genetically match them. They want to know who the closest matches are, and if those matches have family tree information that they can share. 

However, with all the people testing these days, (some being genealogists and some not) the volume of matches can become overwhelming very quickly. 

Are you one of those people who have way too many genetic “4th cousins or closer” among your DNA matches? Have you ever wondered “What do I do with all these matches?!” If so, keep reading. We’re going to explore some of your options, and most importantly, how to determine how genetically close your cousins really are. 

what to do with your 4th cousins DNA genetic genealogy

Doing the DNA Math on Your Cousins

Math can provide us with a degree of certainty in genetic genealogy. Each of us has two biological parents. We have four biological grandparents, and eight great-grandparents.
too many 4th cousins DNA matches

However, the farther back we go the less we can rely on math.

For example, on paper you should have sixty-four 3rd great grandparents. However, many of us find that the same person occupies more than one slot on our pedigree chart. While this significantly decreases the workload for traditional genealogy, it adversely impacts your genetic genealogy. Especially when it comes to that long long list of 4th cousins you have in your match list at any of the three major DNA testing companies.

Depending on how intermarried your lines are, you may be seeing individuals on your match list that genetically look like your fourth cousins, but they are genealogically your sixth cousins – EIGHT TIMES!  So how can you tell the difference?

There are two parts to that answer: one you can control, and the other you can’t.

Distinguishing DNA Matches with Genetic Tools

While your fourth cousins and your eight-time-sixth cousins may look similar genetically, there are often small clues in the genetics that can help you tell the difference. This distinction can sometimes be detected by a testing company who, through research and validation, has been able to fine-tune their algorithms to detect these subtle differences.

DNA cousins

Your Genetic 4th Cousins

You can participate in this double checking process by using some of the genetic tools that are available to you at Family Tree DNA, or at Gedmatch.com. But since you may not be an aspiring geneticist, let’s focus on the genealogical work you can do to determine if a match is truly a fourth cousin.

Use Google Earth to Plot Your DNA Matches

A fourth cousin designation just means that you and your match are separated by between six and twelve degrees (people). So that might be five back on your chart to your common ancestor, and five down to your match, which would make you true fourth cousins. It could also be some other permutation of that.

For our example, let’s assume true fourth cousins. That means that the two of you share one of thirty-two 3rd great grandparents (16 couples). In order to find out which set, you have two genealogical identifiers: surname and location.

Therefore, the first thing you should do is make a list of the surnames and locations of those thirty-two 3X great grandparents.

Now, most of us do not know all 16 of those couples, so you are going to have some holes. Feel free to fill in those holes with surnames on subsequent generations that will carry through to this fifth generation.

A great tool to plot your own list of ancestors geographically is the free downloadable Google Earth software

Check to see if you have the latest version of Google Earth downloaded to your desktop or laptop computer. On your desktop, look for a grey and white globe. If you see a blue and white globe, you have the older original free version of Google Earth. However, a few years ago, Google made their Google Earth Pro version free to everyone, and it is now the standard. 

If you do have Google Earth Pro (the grey globe software) then you’re ready to go.

Google Earth on your computer desktop


The grey Google Earth globe on the desktop.

If you don’t have it, then you will need to download it. 

How to Download the Free Google Earth Software:

  1. Go to http://www.google.com/earth/download/gep/agree.html
  2. Click the blue download button
  3. Read the Terms and Conditions
  4. If you agree to them, click the Agree and Download button
  5. Follow the installation guide
  6. When complete click Run Google Earth

Now that you have Google Earth, you can begin by creating a folder in the Places panel in Google Earth devoted to your 16 couples. Here’s how:

1. In the Places panel, right-click on MyPlaces and select Add > Folder:

how to create a folder in Google Earth Layers panel for DNA

Right-click on MyPlaces > Add > Folder

2. Name the folder and then click OK:

Creating a folder in Google Earth

Creating a folder in Google Earth

3. Now you will see your new DNA folder for your 16 couples in the Places panel. If you don’t see it, look toward the bottom of the list. You can move the folder to any location within the list by dragging and dropping it. 

Create a folder in Google Earth for DNA 32 couples

Create a folder in Google Earth for DNA 16 couples

Once you have your DNA folder created fro your 16 couples, you can then easily plot your surnames and locations. 

How to Plot Your Surnames and Locations in Google Earth:

1. Click your new DNA folder to select it. This will ensure that the placemark you are about to create will be stored in that folder. 

2. In the search box (upper left corner of the Google Earth software) type in the first location and click Search. Google Earth will fly to that location on the map.

Type the locaton in the Search box and click Search.

Type the locaton in the Search box and click Search.

3. In the toolbar along the top of the screen, click the placemark button to place a pushpin in that location:

Click the Placemark button in the Google Earth toolbar

Click the Placemark button in the Google Earth toolbar.

4. In the Placemark dialogue box, enter a title for hte pushpin placemark. Click the OK button to close the box and set your placemark.

5. Repeat the process for all the locations. 

Then evaluate the fifth generation of your fourth cousin matches for genealogical information that lines up with any of the items on your list.

You can also plot the surnames and locations of your matches in Google Earth. This is where Google Earth really comes in handy. The free software makes it very easy to see when your ancestral home may be bordering the locations of your matches. Those with whom you find a similarity become your best matches, and your best chance of determining your connection. Those without an obvious connection cycle to the bottom of your pile for a genetic evaluation. You can perform these same kinds of searches for your second and third cousins as well.

As you begin to become more familiar with the fifth generations of your matches, you may also start to see patterns of surnames or locations emerge among your matches. These then become the surnames and locations that might be able to fill the missing spaces in your pedigree chart.

More Genetic Genealogy and Google Earth Gems

If you are new to using Google Earth, I have several suggested resources for you by Lisa Louise Cooke:

Premium podcast 131

Learn more in Premium episode 131.

Here’s a video of the authors discussing three common DNA misconceptions:

 

 

Authors: Diahan Southard and Lisa Louise Cooke

Organize DNA Matches in Your DNA “Drawer”

Organize DNA matches with this innovative approach. If you are feeling overwhelmed with your DNA results, you are not alone. Learning to organize your DNA matches in an effective way will not only keep your head from spinning, but will help you hone in on possible matches that will break down brick walls. Here’s the scoop from Your DNA Guide, Diahan Southard.

organize your DNA matches

I can tell whose turn it was to unload the dishwasher by the state of the silverware drawer. If either of the boys have done it (ages 13 and 11,) the forks are haphazardly in a jumble, the spoon stack has overflowed into the knife section, and the measuring spoons are nowhere to be found. If, on the other hand, it was my daughter (age 8,) everything is perfectly in order. Not only are all the forks where they belong, but the small forks and the large forks have been separated into their own piles and the measuring spoons are nestled neatly in size order.

Organize Your Imaginary DNA Drawer

Regardless of the state of your own silverware drawer, it is clear that most of us need some sort of direction to effective organize DNA matches. It entails more than just lining them up into nice categories like Mom’s side vs. Dad’s side, or known connections vs. unknown connections. To organize DNA matches, you really need to make a plan for their use. Good organization for your test results can help you reveal or refine your genealogical goals and help determine your next steps.

Step 1: Download your raw data. The very first step is to download your raw data from your testing company and store it somewhere on your own computer. See these instructions on my website if you need help.

Step 2: Identify and organize DNA matches. Now, we can get to the match list. One common situation for those of you who have several generations of ancestors in the United States, is that you may have ancestors that seem to have produced a lot of descendants. These descendants may have caught the DNA testing vision and this can be like your overflowing spoon stack! All these matches may be obscuring some valuable matches. Identifying and putting those known matches in their proper context can help you identify the valuable matches that may lead to clues about the descendant lines of your known ancestral couple.

In my Organizing Your DNA Matches quick sheet, I outline a process for identifying and drawing out the genetic and genealogical relationships of these known connections. Then, it is easier to verify your genetic connection is aligned with your genealogy paper trail and spot areas that might need more research.

This same idea of plotting the relationships of your matches to each other can also be employed as you are looking to break down brick walls in your family tree, or even in cases of adoption. The key to identifying unknowns is determining the relationships of your matches to each other.

Step 3: See the relationship between genetics, surnames, and locations. Another helpful tool is a trick I learned from our very own Lisa Louise Cooke–that is Google Earth. Have you ever tried to use Google Earth to help you in your genetic genealogy? Remember, the common ancestor between you and your match has three things that connect you to them: their genetics, surnames, and locations. We know the genetics is working because they show up on your match list. But often times you cannot see a shared surname among your matches. By plotting their locations in the free Google Earth, kind of like separating the big forks from the little forks, you might be able to recognize a shared location that would identify which line you should investigate for a shared connection.

So, what are you waiting for? Line up those spoons and separate the big forks from the little forks! Your organizing efforts may just reveal a family of measuring spoons, all lined up and waiting to be added to your family history.

More on Working with DNA Matches

How to Get Started with Using DNA for Family History

Confused by Your AncestryDNA Matches? Read This PostOrganize DNA matches quickguide

New AncestryDNA Common Matches Tool: Love It!

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