What Are the Grey Squares on a DNA Match Cluster Chart?
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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Aren’t they really all grey squares?
If I understand it correctly the colouring is an artifact of the software and appears to be related to the ‘density’ of relationships between matches. A hint that the block might be a branch of descent from the MRCA.
In my observation the squares left grey indicate that either the match descends from a more recent ancestor than the ones in the coloured blocks or that the match that is a generation or two older than the rest.
Hi, Gavan. I’m not sure what you mean by “aren’t they all grey squares?” Most of them should be white though perhaps they look grey in these photos.
I’m also not sure what you mean by “an artifact of the software.” You might read this more recent post for a better explanation of the matrix: https://www.danaleeds.com/understanding-cluster-matrices/
As far as your observation about the grey cells being more recent or more distant ancestors, that is quite interesting! I know I have observed it at times, but I’m not sure that it’s always the case. I think at times it could be that the grey “people” are descendants from a different sibling. But it’s something I’m going to look into more.
I manage the DNA of a friend who was adopted. I have confirm her birth mother’s identity but have not been able to find her birth father. Her AutoCluster chart from MyHeritage has more grey squares than coloured ones! Most of the grey squares are either singles or in groups of 2. Would this be a sign of Endogamy do you think? Although her father was listed in her adoption papers as being “English Canadian” most of her DNA matches are “French Canadian” names. There is a lot of inter-marriage of French Canadians and I’m beginning to believe that her birth parents were related.
Hi, Diane. Sorry for the delay! There were 2 messages that I could “see” but “not see” and yours was one of them. But today I was able to access them! I’m not sure what happened!
Yes, unfortunately a bunch of gray squares on MyHeritage’s AutoCluster is a sign of endogamy. And, yes, there is a lot of intermarriage with French Canadians! It will probably be a tough case! Best wishes!
Thank you for such a clear explanation of grey squares have been struggling with that part for a while.
I admire your knowledge.
I am also struggling to find which coloured square is my deceased Mother’s father as she was adopted.
My strongest match to my Mother’s Mother has matches in lots of my coloured squares.
Found (after my 40 years researching) through a wonderful Search Angel, Mum’s Mother………..he said it was the hardest he had done but he had give up on her Father as too many Welsh surnames.
I suspect endogamy as most of my dna matches family trees show descendants from villages in Anglesey Wales U.K.
I am on a steep learning curve with this dna but you have helped….thank you!
You’re very welcome! And glad a Search Angel was able to help with at least one side.
Dana
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