Adding a GUESS
Setup
gk (Match1) is known 5C1R – with grandmother: Anetta b 1926 m SURNAME1 > father: private Male > gk; AND gk has 10 known 2C to Anetta’s father (in the line going back to our MRCA).
Justin (Match2) shares 898cM (estimated 1C) to gk; and has a very small Tree of Private Ancestors.
Analysis
To be a 1C to gk, Justin would need to share grandparents with gk – either gk’s paternal grandparents or gk’s maternal grandparents. From the setup (above), we know the maternal grandparents are SURNAME1 and Anetta b 1926; we don’t know (but can often find) gk’s paternal grandparents. In this case there wasn’t enough info in Justin’s Tree to help.
However, there is another way to determine which set of grandparents Justin descends from. If he descends from Anetta’s side, Justin would also be 2C to the 10 known 2C that gk has (NB: all 2C match each other). If Justin descends from the other grandparents of gk, it is highly likely that Justin will NOT share any of the 10 known 2C to gk. A quick look at Justin’s Shared Match list, shows he matches ALL of the same 2C that gk has. Justin is clearly a 1C to gk on gk’s maternal side – which is the side back to the MRCA with me!
Therefore, I am very confident in adding Justin to my Tree with UNKOWN parent and KNOWN grandparents: SURNAME1 and Anetta b 1926. The rest of the path gk has back to our MRCA is already in my Tree.
This places another Match into my Common Ancestor spreadsheet and into my Tree. It takes this Match off the list of unknown (aka Mystery) Matches. In Shared Match lists, Justin will now show up as a known (Dotted) Match – reinforcing Clusters. I don’t know if Justin’s addition to my Tree will help AncestryDNA with future ThruLines evaluations, but I hope so. I *know* it will help me.
A similar analysis can be made for a Pro Tools estimate of 1C1R or a 2C, but it gets less reliable with each additional degree of separation. There is also a higher degree of difficulty in the analysis, because the certainty of the cousinship estimate is not as assured and the number of possible alternatives that need to be addressed increases. It’s often not impossible, but it is harder. A strong factor is whether a *candidate* Match shares a lot of the same Shared Matches. In other words, if the candidate Match clusters with a lot of the same Shared Matches (which can be observed in the Shared Match list), to me that is a strong indication that candidate Match has the same MRCA. This needs to be tempered with endogamy or pedigree collapse – judgment is needed in those cases.
[22DC] Segment-ology: Pro Tools Part 21 – Adding a GUESS by Jim Bartlett 20250109
segment-ology 
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One topic I have long-considered writing-up as a blog entry, or forum post, is the value of an educated guess. In some cases, especially now with the information provided by Ancestry’s Pro Tools, placements of matches can be better than guesses, even if we do not have precise names for all people in the line of connection.
I have made many private and unsearchable trees based on multiple initial guesses, and let Ancestry do the work of finding more documentary evidence for me to consider. Even when the guesses are a bit off, Ancestry can often turn up relevant documents anyway.
There is also some value in using our imagination, or guesswork, as a tool to filling in the blanks in our ancestor’s lives. I had one particular cousin with a puzzling marriage record. Many times, I wondered how she would have met her spouse and ended up in the location in which she married him. However, I happened to watch a TV documentary about aspects of life in the Victorian era in Britain. This was the time period in which this particular relative lived. One point in the show sparked a tangential idea. I created a story in my head about the unique circumstance of my cousin meeting her future spouse. I became convinced the story was a good possibility, So, I began searching British newspaper archives, using various search terms related to my imaginary tale of the encounter. Small details of ordinary lives were often the subject of short entries and I thought that this story, if true, might have merited an entry. It was a moment of research triumph when I located a short article, reporting the story exactly I had imagined. I hope to write-up this whole story some day because that is just the start of a fascinating tale.
I think that because genealogy and genetic genealogy both require detailed work, and demand a research standard that is “exhaustive,” it can be easy to lose sight of the value of a bit of imagination, creativity, and fill-in-the-blank, as part of the exhaustive exploration of all avenues to solving a problem Of course, in the end, we still substantiate our work, but creating a bit of scaffolding for the work in progress can go a long way.
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tetleyt – I agee with you 100%. Genealolgy is a hobby for most of us; and we each get to decide what our objectives and methods will be. The “industry” and some professionals have provided some excellent guidelines that will help us be successful. But there will always be tradeoffs between our limited time and what we want to accomplish. I hope you’ll send me a link to your Victorian era story – and/or I’d be happy to host a blogpost for you. As an engineer, I like your “scaffolding” idea. Each of us humans have 2 bio-parents and humanity is a jigsaw puzzle that interlocks only one way. When we get the pieces together the right way, all the interrealtionships will fall into place – just like a real jigsaw puzzle. I think Pro Tools is really accelerating the process for me.
Thanks for your comments. Jim
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I will certainly let you read the Victorian story. At this point, I am looking for a couple of additional records which may or may not exist. They are not essential to the story but would round things off nicely. I also have several images to go with the story and am checking on any copyright issues.
Thank you for the hosting offer, it would be a great way to dabble with writing blog entries.
I am enjoying your Pro Tools series because I am also very enthusiastic about the information it provides.
Your description of Pro Tools as accelerating the process is spot on. I can barely keep up with investigating or recording all the interesting things Pro Tools reveals. While there is a lot of data to handle, I am finding it easier to solve multiple matches at once. I always liked the matrix tool on GEDmatch. I have a matrix I am working on right now on my mother’s kit. Each unknown match is picked for the matrix if they share 100 cM or more with one of my mother’s known matches on a particular line. The known match also goes into the matrix. This is coming along well. It became quite obvious where people would have to fit in. This helped with focussing the paper trail search. I have already placed a few matches and, in the process, learned what became of some lines of descent.
Even distant matches get a boost from Pro Tools. I enjoy the ability to more easily build and merge clusters of matches several times over, building back the tree of the matches as I go. While not every tree built this way can be connected to my own, yet, each one has provided fascinating details about my extended tree and the connections of cousins to times, places, and events in history.
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tetleyt – you raise an interest perspective: just because there is a Cluster of Matches which includes a known-relationship Match that doesn’t mean the Cluster is related the same way. I might be related to the known-relationship Match through her father; while the Cluster could be related through her mother. That’s why we have to check the Cluster Matches to insure they match others on her father’s side – other Matchs outside of the Cluster (or find some other way to determine which side of her Tree they are related on (sometimes we are dealing with a Cluster of Matches with no Tree, just that they are closely related per ProTools…. Jim
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That is very true. A lot of additional work goes into examining those clusters (plus a bit of segment information from other sites). I have one diagram showing how a cluster of my sister’s matches are almost all paternal to her, but a few are maternal (as per SideView). On my mother’s account, the few people from my sister’s cluster are divided with some maternal to my mother but some are paternal with shared matches to some of my mother’s known paternal matches. So, essentially Ancestry is suggesting my sister’s cluster represents possibly 3 of her lines. Fortunately, with all the tree building to connect the clusters, I can also diagram the point (as well as having the paper trail ) to show where my sister’s mainly paternal cluster, connecting back to Dundee Scotland, marries into my mothers maternal and paternal descendant lines, likely from Dublin and Belfast respectively. This occurs in Utah, USA in a Mormon settler community. I think this particular analysis is a good one for demonstrating the complexity of the relationships that can be hiding in a cluster. It is quite fascinating that DNA reveals stories of historical movement and connections of three lines coincidentally coming together on both sides of the ocean.
I suppose besides SideView, we have other workarounds for managing clusters and checking the lines of connection. Ethnicity is one, especially when we have matches who do not have much in common with us at a continental level. Asking matches which line we are on from their perspective helps, too. In the end it all comes down to the same thing. No matter which way we go at it, we give every investigation as extensive an analysis as possible, and then try to poke holes in it.
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