Leeds Method of DNA Color Clustering

Marc McDermott

In this article, I want to discuss the Leed’s method and provide some examples to allow you to approach this technique with clarity and understanding to help you to put this practice to use within your own genetic research.

The Leed’s Method was termed by Dana Leeds, a genealogist who works as a “Search Angel” sorting through DNA matches on unknown parentage cases. She implemented a strategy to color coordinate DNA matches in a spreadsheet which allowed her to determine which DNA matches were related to each other.  See the example below from danaleeds.com.

This creates a visual aid and depicts groups of cousins. Each group, generally four of them, will represent a grandparent’s ancestry and they should be able to trace each group of DNA matches back to a CA (common ancestor).

The Leed’s Method is extremely beneficial for working unknown parentage cases and even working law enforcement cases. When working an unknown parentage case or unknown identity case and you do not do any grouping, it is essentially taking a shot in the dark. When you do not group together matches you are likely to get overwhelmed and frustrated.

The first rule in working on these types of searches is to establish your groups. Ancestry recently rolled out their color grouping system which acts much like the Leed’s Method.

The easiest way to put your groupings together is by using the “shared matches” between you and your DNA matches. If you know your mother and you are searching for your biological father, finding a maternal cousin would allow you to quickly view “shared matches” and, if your parents are unrelated, you would have your maternal and paternal groups already established. When you have your paternal and maternal groups separated you can continue to break your maternal matches into more groups, again usually two. Same with the paternal matches.

If you have no idea which groups correspond with your maternal or paternal side, that is okay. As long as you see the different groupings, that is all that matters. Eventually, the puzzle will all come together. You just have to be persistent and, most importantly, patient.

Why group your matches?

By undergoing a sometimes arduous task in grouping your matches, you are alleviating a lot more stress. When searching for your ancestry by using DNA matches you are entering knowing almost no knowledge (especially if you are adopted and have no paperwork – even paperwork can be misleading). DNA never lies.

When you group together your matches, you are creating a visualization of your genetic networks. Each group, also called clusters, will correspond with a common ancestor which will ultimately be your ancestor as well. By locating these common ancestors you can begin creating a family tree and reverse engineer how YOU fit into it. As I said, each group will correspond with a common ancestor and the more matches you can take back to a common ancestor, the more luck you will have when reverse engineering your biological line to that common ancestor.

On DNAPainter they offer the WATO tool (WATO – What Are The Odds) which is an algorithmic chart with which you display your DNA matches and how they link back to your common ancestor. By inputting into the chart the number of centimorgans you share with your matches, you can input the hypothesis (which will represent you) and the hypothesis will spit out a number that will dictate the likelihood of your fitting into the tree as displayed on the chart. The hypothesis with a score of 1 would represent it is likely. Anything higher than 1 would mean it is “x’ times more likely than the hypothesis with a score of 1. We can go more into the WATO chart at a later time.

How to find shared matches

On Ancestry, while also viewing the profile of a DNA match, there are tab options on the profile. By default, you will be shown their “Tree”. You will choose the “Shared Matches” tab to the right and this will then display all of the matches with whom you and the chosen match have in common.

On 23andMe when viewing the profile of a DNA match, scroll all the way to the bottom, and you will see an option to “Find Relatives in Common”. When displayed, a table populates which shows you and your matches mutual DNA matches. Most helpful is that is shows you how much DNA you share with a mutual match as well as how much DNA your DNA match (who profile you are viewing) shares with them as well. Ancestry and FamilyTreeDNA do not have this option.

On FamilyTreeDNA, while displaying your DNA matches, you will see white boxes to the left of their names. By choosing the match you’d like to see your common matches with, select the box (it will turn blue with a white check mark) and the above the matches table is an option to view “in common with’ matches. This will display all of the matches you share with the selected DNA match.

On MyHeritage, when viewing the profile of a DNA match there is a section of the profile which automatically displays shared matches. MyHeritage displays the amount of DNA you share with mutual DNA matches as well as how much DNA the match who’s profile your viewing also shares with the mutual matches. This is incredibly beneficial as Ancestry and FamilyTreeDNA do not have this option. 

On GEDmatch, there is a tool which allows you to view common matches between two GEDmatch Kits. This will display which matches your kit and other kits share while also showing you which kits don’t match the others. This is beneficiary but does not always mean there is triangulation involved between your kit, the kit you are running the tool with, and the kits that populate.

Other Tools for Grouping

Though I am a believer in sorting DNA matches manually to better help you familiarize yourself with their trees, surnames, and mutual matches, there are tools which can do things automatically. These tools can expedite the grouping process exponentially. Unfortunately, Ancestry no longer allows third-party tools to access your match list so it still needs to be done manually with the Leeds Method.

There are cluster tools which display an X and Y axis on a graph. Both axis display your DNA matches and shared DNA between the matches on the X and Y axis populate in a colorful chart which display larger groupings on the top left and smaller groupings following in a diagonal descending pattern. Generally, with good grouping you will get a cluster chart that resembles a very colorful and pixelated wand. Each box will represent a group of DNA matches who all relate to the same common ancestor(s).

MyHeritage (example displayed below) clustering tool is generally behind a paywall for users who upload their data from other sites. GEDmatch also offers a cluster tool for their tier one users ($10/month). FamilyTreeDNA, also behind a paywall, offers a family-matrix tool which can do the same type of visual representation with you and ten other matches of your choosing.

My personal favorite for grouping is a pen and a legal pad. To each their own, I suppose!

Regardless of how you put together your DNA matches into groups, it is the first step you should take in the journey of locating your unknown parentage or even if you’re just wanting to keep things organized. If you do not group your matches you will be burnt out with trying to connect the dots.

All of the sites offer different tools and benefits as discussed above but, Dana Leed’s really pioneered the grouping technique. For more about the Leed’s Method and the exact process to follow, visit Dana Leed’s website here.

About the Author