Both AutoClustering and the Collins Leeds Method (CLM) create DNA Match Cluster Charts. The charts have colored clusters of people who are likely descended from common ancestors. Yesterday, I talked about how I analyze the clusters. Today, I wanted to explain more about the grey squares that are outside of the colored clusters.
Above is the same CLM chart I shared yesterday. Each color group is a “cluster.” Below is a chart a friend – John Motzi – made representing the same data. I had categorized each cluster as belonging in group A (dad’s dad), B (dad’s mom), C (mom’s dad), or D (mom’s mom). He simplified the chart by creating blocks of color and adding the letters: A, B,C, or D.
John also simplified the grey cells that are outside of the Color Clusters. The grey cells indicate likely relationships between two Color Clusters.
Each of these charts shows mirror images reflecting on a line going from the upper left to lower right corner. John has shown 4 grey areas above and below the Color Clusters, but they are mirror images. Let’s look at the 4 grey areas below the clusters.
To determine which clusters a grey cell is indicating a possible relationship between, we look both vertically and horizontally. The cells should run into a Color Cluster in both directions.
First, we have the thin grey block of cells to the left of the 3rd cluster: a “C” cluster. If we look up from those cells, we run into the 2nd cluster, which is also a “C” cluster. This indicates that the two C groups are related to each other. That makes sense!
If we look at the next two large grey groups, we have one that is intersecting two different D groups and another that is intersecting two different C groups. Again, this makes sense!
The last grey group is a single cell representing two DNA cousins. This intersects the only B and the only A group on the chart. Remember, A and B represent the dad’s dad’s side and the dad’s mom’s side. In this case, both families came from the same small town so it is likely that some matches are related to both groups.
(I did take a closer look at these two people. Unfortunately, neither cousin has a tree and neither has been logged in for at least 6 months. They are both good matches at 235 cM and 129 cM, so I’d love to identify them at some point.)
How can these grey cells help you? Let’s say you have a cluster in which you cannot identify anyone. If you have some grey cells indicating a relationship between that cluster and another cluster, you can use this hint to help you start identifying some of the cousins and identifying their place on your family tree.
If you have any questions (or suggestions) about the grey squares on this example or your own charts, please ask!
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