This is hard to describe… I want to explain how to work from Matches who share a Common Ancestor in one generation back to some Matches who will share a Common Ancestor another generation back.  Say I have a group of Matches that all share the CA A38/39 (using Ahnentafel numbers). In my case this is Joseph ALLEN b 1775 and his wife Elizabeth (unknown maiden name).  You Segmentologists can probably already see where I’m going… How can I find a bunch of Matches that I’m sure are from Elizabeth – so I can look at *their* Trees and find *their* CA, who would almost certainly be my Brick Wall CA?

What I’m going to describe is a method we can try after all other genealogy research and DNA analysis have failed. As Segmentologists know, I believe our two main grouping methods (Clustering and Triangulation) each point to a CA, whether I know who that is, or not. I see too many Match Clusters and Match Triangulations that group on known CAs. To me, it stands to reason that they would also group on unknown CAs – Brick Walls, or unknown Ancestors even further back.

The setup:

Objective 1 – find Matches with a known CA (in this case A38). ThruLines is a big help. Then use Shared Matches and Pro Tools to pile on – find as many additional Matches as possible who descend from the A38 family. As we know, the DNA may be from the A38 or his wife A39.

Objective 2 – keep working the lists of Shared Matches of Matches (SMOMs). We may find a few more Matches with an A38 CA. We may find some Matches who have known CAs that are not A38 – this is normal. What we are looking for are Matches who are each on the SMOM lists of each other. In general, if they match each other, that means a Cluster and a CA – an unknown CA. Quite possibly the parents of A38 or A39. We have the surname for A38, so can readily determine if that group is focused on A76/77. Set them aside, it’s the other group we are interested in. It could well be from the CA we want: A78/79 (the parents of Brick Wall A39. We have to look at *their* Trees and determine *their* CA.

That is the concept. Now a little more in-depth study.

1. A38 is what I call a 3-4-5 Ancestor – a 3xG grandparent couple; normally a 4C level (mostly 4C1R or 4C2R for folks my age…); and 5 generations back.

2. My experience is that most of the time, the close shared Matches closely match each other within the 3C level. This means from my 3-4-5 Ancestor couple, at the 4C level, the closest Matches to each other among the Shared Match lists, form on the children of the CA. In this case on the children of A38/39. This happens all the time in my CA spreadsheet – Clusters are apparent for each of the children of a 4C Ancestor; for each of the grandchildren of a 5C Ancestor, etc. Not always exactly – but definitely a trend. In my case for A38/39, they had confirmed children: John 1802 > 21 Matches – all but 3 Cluster (and those 3 are from an iffy grandchild I cannot prove), average 15cM; Joseph E 1808 > 7 Matches all Cluster, avg 17cM; William H 1815 > 19 Matches, avg 17cM; Joshua R 1816 > 31 Matches, avg 20cM. The Matches in each Cluster tend to be within 100-3,500cM range of each other – they are parent/child, siblings, aunt/uncle/niece/nephew, 1C and sometimes 2C to each other. Dropping below 100cM on a SMOM list is not usually worth my time. Note: this is all done on a SMOM list sorted by Match cMs (not by my shared segments).

What got me started on this new concept, is thinking how Matches on who were related to me another generation back would show up. Well… in the first place they would generally be smaller cM shared segments. And they would be “removed” from the Matches I had already identified – another generation back! Wow, just what I wanted!!

I know (lots of trial and error) that as I work down a SMOM list, more and more of them have CAs with different, almost always random, Ancestor lines. But not always different – sometimes ThruLines has already found a Match farther down the SMOM list that Matches the line I’m working, and sometimes a generation, or even two, back.

This seems reasonable to me, the smaller the cMs down the list, the wider the range of possibilities of CAs. Remember the much larger cMs at the top of the list tend to be closely related to the known Matches.  Couple this with my belief that most of my Matches are in fact related to me in a genealogy timeframe (8C for me). The problem is not false data or very distant Ancestors, it’s the lack of good Trees. So I’m convinced that many (not all…) of my Matches down the SMOM list are 8C or closer. And within that pretty large group of Matches, there are many who descend from my Brick Walls.

This concept results in a “Floating Branch”, but one that has shared-Match links to a known CA. In a previous post, I’ve opined that strong Floating Branches *should* pair up with Brick Walls – it’s like an almost completed jigsaw puzzle – a few left-over pieces and a few bare spots in the picture – they must Match up.

For my part, I’m going to try this on A38/39…

I’m curious and interested in your experience (and logic). Have you “clustered” through a Brick Wall? Do you think my “concept” here will work? Looking forward to your feedback.

[06K] Segment-ology: A Segment Concept; by Jim Bartlett 20261107