Ancestry has been rolling out its clustering feature this past week to those of us with a Pro Tools subscription. If you have it, there is a new button at the top of your list of matches with an icon that says “By Cluster.”

The purpose of clustering is to create an easy-to-use visual way of organizing DNA matches that are related to you and to each other. The graphic sorts the matches who share 65 cM to 1,300 cM with you into groups who also share at least 20 cM with each other. Each match is listed in the rows on the left as well as by initials at the top for each column. In a perfect world, you would get four colored boxes, like in the image below, where each box represents the line of one of your grandparents.

The image above has actually had the top box truncated and two additional boxes removed for illustration purposes. The left side would have the full name of the match while the top has just the initials.

Below the diagram there is  a list of the clusters. Click on any one to see the members of that group. Notice that each member has all the information you would see about that person in your match list. Another nice feature is that you can add everyone in a cluster to a colored dot group by clicking on the “+ Add All” button.

While this sounds like a wonderful new tool, for many of us it needs the ability to specify the range to include in order to get the best boxes. Below is what a Jewish friend of mine gets; lots of clear small boxes, but everyone is related to everyone else outside of the clusters, except for her middle box. This is what endogamy looks like!

And my own clusters only come up for my paternal Norwegian side and because so many of my first cousins and their children and grandchildren on that side have tested, everyone really is related to everyone. Same problem with my brother’s clusters. Not useful without the ability to change the range of numbers included. That is coming soon as there is a “Custom” button which is currently grayed out. For me, I just want to group my second and third cousins or maybe even just the group in the “extended family” bin.

My own clusters are only for my paternal Norwegian side

A strange problem occurs when I look at my late jewish husband’s clusters, he only gets one small one. Although his parents came here in the 1940s, he still has many American maternal side relatives. It would seem that his huge Tieger family (14 in that group that fall in the correct range)  is not included for reasons I do not understand. I checked his second cousin once removed and she has a nice group of three clusters, the middle one includes seven of those Tiegers. I need to follow up on this with support.

Then there are the people who have so few matches that they get the message “We’re sorry, we couldn’t cluster your matches.” Plus those with so many matches that they do not get the visual clusters, although they get the groupings below the message “Chart view is available for clusters of 100 matches or fewer.” I am fortunate to have helped so many people over the years that I get to look at many of these diagrams.

Both MyHeritage and GEDmatch have had clustering tools for a long time and they both allow the changing of cM parameters for the groupings. Click here for my 2019 article about clustering on those sites.

However the Ancestry implementation has the benefit of a much larger database. They also use good strong colors and have an attractive presentation. I look forward to when it includes the ability to customize the range!