Clustering your DNA matches can help you make sense of that long list of unknown DNA matches. Although there are programs that now automate clustering, you might want to try it yourself. What are the advantages of creating genetic clusters manually? You might enjoy working with each match and discovering your shared ancestral lines. Each testing company website enables you to view people that share DNA with you and with your DNA match. Shared DNA match lists and in common with (ICW) lists can help you learn which side of the family your DNA Matches are related to you. A known first or second cousin can be beneficial to determine if a DNA match is on the paternal or maternal lines.
Each testing company approaches the shared matching slightly differently with a unique name and way of displaying the information. As you use the features available at each website, you can manually separate your list of matches into groups.
Ancestry: Shared Matches
Ancestry uses the term “Shared Matches.” When you click on one of your DNA matches, you’ll be redirected to a page that shows more information about your DNA match. You might see that you and your match have a common ancestor if you both have trees that include the same individual. You’ll also be able to view shared ethnicity estimates. The screenshot below shows my first cousin, once removed, Lucretia. We share DNA through William Huston Shults and Dora Algies Royston, so any shared matches will also share a common ancestor somewhere back on that line.
Clicking on “Shared Matches” on this page will list individuals who match both you and your DNA match. Ancestry has the added feature of using colored dots to group people into genetic networks. You can work with the colored dots any way you choose, but it might be helpful to think through a system before beginning.
A DNA match may have as many dots assigned to it as desired. For instance, an initial dot for maternal or paternal could be assigned, and then further dots added as more information is discovered. Pedigree charts often use blue and green for the paternal line and pink and yellow for the maternal lines. You could follow this practice in assigning the colors to your matches. I’ve followed this pattern, and you can see in the screenshot above that I’ve assigned a green dot for any matches descending from William Huston Shults and Dora Algie Royston.
For an excellent system using the colored dots, see Leah Larkin’s article, “Quick Tip: Color Code Your Ancestry Tree.”
Try it: For any DNA match, click “Add to group” then “Create custom group” to create a custom group and assign a color to that group. It will then appear in your list of groups. Click the box next to the dot to add that group to a DNA match. The custom groups can be edited at any time. When viewing a new DNA match, clicking “Add to group” will allow you to select any custom group you have created or create a new custom group. Each group has a color assigned to it by you.
FamilyTree DNA: “In Common With”
FamilyTree DNA provides two tools for shared matching – “In Common With” and “Matrix.” These will help to discover a cluster of individuals who share DNA with you and with each other. When I want to discover shared matches with Lucretia on FamilyTree DNA, I can use the “In Common With Tool” to find those DNA matches who share with both of us. I found that I had 189 paternal matches and 1 maternal match (I have only one instance of overlap in my maternal and paternal pedigrees).
Using the Matrix tool, I can select up to ten people and see if they share DNA with me and with each other. I selected the top six matches between Lucretia and me to see if they also shared DNA with each other. FTDNA created a matrix shown in the screenshot below, and you can see that Lucretia and I share with all of the matches. Each match is represented twice – across the top and down the left side. If they match with each other, the box is colored blue and marked with a checkbox. The gray squares on the diagonal show where the same person intersects. The people that also match each other share a common ancestor with Lucretia and me on different branches of our tree.
Try it: Go to myDNA > Family Finder > Matches. Click the box next to the DNA match you’d like to explore, then “In Common With” at the top of your match list. The list will then repopulate, and you’ll see a filtered list of individuals. These are on your DNA match list and the DNA match list of your selected DNA match.
Try it: Go to myDNA > Family Finder > Matrix. Select up to ten individuals to see which of your DNA matches also share a genetic relationship with each other.
Additionally, if you have a family tree on the website, you can link a known maternal or paternal DNA match using the feature titled “Family Finder – Family Matching.” This will phase your DNA test, assigning maternal or paternal icons to each DNA match so at a glance you can determine which line a match is on. See the website for complete instructions on using this feature.
23andMe: Relatives in Common
23andMe uses the term “Relatives in Common” and allows you to see genetic relatives you have in common with a specific DNA match. The website creates a table of Relatives in Common by looking at your DNA Relatives list and checking to see if any other relatives on your list share at least 5cM of identical DNA with your match.
I’ve selected my first cousin, Cindy, and I see a list of many shared matches in the screenshot below. What is unique about this reporting is that 23andMe also shows me how much DNA Cindy shares with each of our shared matches. As expected, she shares DNA with my mother since our mothers are sisters. She also shares DNA with her sister, who is also my first cousin. This additional information about DNA matches can help to make connections and discover relationships.
Try it: Go to Family & Friends > View All DNA Matches. Choose a match to explore in-depth; click on the name or the circle. A new page will appear with information about your genetic relationship and comparing family background and ancestry composition. Scroll down to the bottom of the page and click on Relatives in Common to show those DNA matches that share DNA with both you and the selected match.
MyHeritage: Shared DNA Matches
MyHeritage provides shared matching as well as a chromosome browser to view triangulated segments among shared matches. This capability makes this feature particularly powerful because it lets you identify whether the shared match group of three individuals all share a common segment. If not, that could signal that the three people are related in another way.
When I looked at the shared matches between me and my first cousin, Cindy, I was again shown a list of individuals. Because I’ve uploaded DNA for my mother and some of my children to this site, they are at the top of the list. As you can see in the screenshot below, MyHeritage reports how much DNA I share with my daughter, Nicole, and how much Cindy shares with her.
Clicking on the pink icon to the right, I can see the triangulated segments where all three of us share DNA – depicted by the rectangles in the screenshot below. You can select up to seven DNA matches to compare segment data.
Try it: Go to DNA > DNA Matches. Click on “Review DNA Match” to the right of the individual you’d like to learn more about. The webpage will refresh and show a table labeled “Shared DNA Matches” with information about the amount of DNA shared and a possible relationship. Below the table are an ethnicity comparison and chromosome browser. If there is a triangulated segment between you and your DNA matches, that will appear on the far-right side in pink. Click on the icon to view the triangulated segment(s). Select additional matches for further analysis.
Dana Leeds created a manual clustering tool in 2018 using a spreadsheet, color coding, and the testing company’s shared matching tools. Originally designed for unknown parentage cases, it also works well for doing an initial sort of your DNA matches. After the method became widespread, automated tools were created to shorten the time it takes. However, trying Dana’s method for yourself will give you a better understanding of how clustering works. See her website for tutorials.
Best of luck as you experiment with clustering your DNA matches!