In genetic genealogy, DNA is a tool. It helps us, in many different ways, to determine Ancestors and confirm cousins. My point in this blogpost, is that we don’t need to know precisely how we are related to each cousin – a calculated guess is fine. In fact, I encourage it.
Here is an example. I have determined that XYZ is a 7C. This is based on genealogy. We share my Ancestor couple METZGER/KEIFFER (aka Ahnentafel 352). This Ancestor couple’s full names, dates, places, life story are not important to Segmentology. Match XYZ happens to share 15cM, also not too important, but well within Shared cM range. XYZ is on my Paternal side, as is our MRCA. XYZ and I have over 30 other Matches on our Shared Match list – the top 20 Shared Matches share over 100cM with XYZ. I can tell you that this will show up as a strong, solid Cluster. You get the picture; this is pretty solid…
So now I notice on my Shared Match list with XYZ that, per ProTools, ABC is a 1C to XYZ, sharing 852cM. ABC has NO Tree. However, ABC has a long Shared Match list with over 30 Matches who are known cousins to me through Ahnentafel 352. #A0352P is the first thing in many of my Shared Match Notes, which is all I need to know…
There is no Tree for ABC, but as a 1C to XYZ, I don’t need a Tree. I know XYZ’s grandparents, must also be ABC’s grandparents for them to be 1C. So, I confidently add ABC to my Common Ancestor spreadsheet and copy the line of descent I already have for XYZ, and change ABC’s parent to UNK. Done!
I’ve now added ABC to the Shared Match spreadsheet, and can enter a Note for ABC which starts #A0352P. Which Note is now visible to all other Shared Match lists (and Clusters) that include Match ABC. This helps me find even more Matches to evaluate and add.
Emboldened by this logic, I am sure I can also add a proposed 2C to my spreadsheet (with UNK for both parent and grandparent). This will “tuck” many more Matches into my spreadsheet of known cousins, even though I don’t know their parents or grandparents. And those Matches will often highlight other Matches who can be added. For A0352P, I now have 151 confirmed Matches!
Note: It’s important that these potential additional Matches be vetted (as above). They should also be part of an appropriate Cluster of Shared Matches. Even the parent of a known Match can be on the wrong side. That is to say, for instance, my line from XYZ goes through her mother – so her tested father could well show up as a close match to XYZ, and to me, but his path to a CA would be different (ie NOT through his wife to A0352P!).
In conclusion, there are two options:
1. Leave this “Match with no Tree” out of my Tree – disavow them as a cousin because *I* don’t know their parent’s name.
2. Accept this Match as a 7C to me; just as much as I accepted XYZ as my 7C.
To me, as a lifelong genealogist, I’d choose Option 2 in a heartbeat. I’d hug this new Match just as strongly at a family reunion. I’d probably ask their parents’ names… But the rest of their line would already be in my spreadsheet. The UNK parent/grandparent wouldn’t make any difference. And, that Match will now help me document other Matches!
AND, often this new cousin Match doesn’t know much of their Ancestry – be a helpful genealogist, and send them a message about the ancestry you are sure they have… Add their line to your Tree, and ask if they’d like you to add names in place of the UNKs!
This is also a plug for the Common Ancestor spreadsheet – a valuable tool for recording found cousins, and for easily seeing how other Matches fit in. Hard work, but it sure highlights strong branches of my family Tree (as well a weak branches).
[35BCa] Segment-ology: A Calculated Guess Is Great; by Jim Bartlett 20260403
segment-ology 
This same principle can apply, even when someone has a well-documented tree, and their parents, grandparents or even great-grandparents are marked as living, and are therefore private.
LikeLike
Jean – A very good point!! Thank you. Jim
LikeLike
Jim,You said this is a plug for your Common Ancestor spreadsheet. Are you selling it somewhere? I don’t see a place to download or purchase it in the linked post. Robin
LikeLike
Si Jimmy anche le mie 18 match ti ricordi sino alcuni tra loro mezzo cugino 1 gradi tra loro e altri tra loro sono tra 2-3-4-5 grado io con loro secondo mhyeritage tra 4-5 cugino.in questi giorni ho avuto conferma dalle altre corrispondenze che una r rom e altre due misti rom sono da paesi du Ersilia sempre Balcani ricordi la mia triangolazione del segmento tra 7,1-9cM? Ma il condiviso va da 8cM fino ha 23,3cM.
LikeLike
The range from 8 to 23.3cM is within normal range. It’s usual and common to have a range of values because the path of the segments from the Common Ancestor down to each Match is different. In some cases, the segment may pass down through some generations intact (without changing – I call it “sticky” during that time); in other cases the segment may be reduced in size due to recombination and wind up fairly small by the time it gets to the Match. What you are seeing is normal. Jim
LikeLike
I agree … a “Calculated Guess” … very often leads to success. And sometimes it opens up the unknowns to all players in the circumstance. What better way to visualize the actual world of “cousins” … love it Jim …
LikeLiked by 1 person
Thanks John – a great summary. If nothing else, cousins should always help each other out – we’re kin! Jim
LikeLiked by 1 person
ProTools has been a real game changer.
LikeLike
I had a situation with a match that I knew had to be about a 3C on a particular line. I wrote to the match, sharing some interesting general information on this common line and expressing interest in figuring out how we were connected. I received a pleasant reply, but the match indicated I was related to their paternal side, and they did not wish to know who their father was. I thanked them for their reply, and left it open that they could contact me if they ever had any questions about our shared line.
About three months later the person contacted me and said they had read over my messages a few times and they were now understanding that I could actually know who our ancestors were without having to know who their father was. They said they were actually very interested in the family history in general and they wondered if I could provide them with any information about that.
I prepared a little package of links to good web pages all about the history, community and lives of the Paisley (Scotland) weavers. I included information specifically on our common line of Paisley weavers and some documents showing their occupation fields specifying “fancy shawl weaver,” “hand-loom weaver,” and “pattern setter.” I also noted that even the women usually had an occupation listed on at least one document in their lives as “a weaver’s pirn winder” or a “shawl fringer.” I was able to note which street addresses the family resided at and where their loomsteads were, as per an older map of Paisley from that time period which really emphasized the hub of the textile industry.
So, although I did not have quite enough DNA match information to put this match precisely in my tree, I knew enough about where they belonged that it was sufficient to be of help.
LikeLiked by 1 person
Lightseeker – What a great story – you are a kind genealogist – this is way it should be. Thank you for setting a great example! Jim
LikeLike