A Segment-ology TIDBIT
In my spreadsheets, Notes and analyses, I refer to Common Ancestors (CAs), or Most Recent Common Ancestors (MRCAs), by their Ahnentafel numbers.
Most of the time the MRCA with a Match is a couple, and I use the Ahnentafel number of the husband. For example: 36P is my father’s father’s mother’s father’s father (or 1-2-4-9-18-36 with the Anentafel number for each generation). This 36P shorthand actually refers to the 36/37 couple (Thomas NEWLON and wife Susan in my case). I add on a P or M to indicate the Paternal or Maternal side, as this is not obvious with larger Ahnentafel numbers after several generations.
Just to keep my bearings, I also usually indicate the cousinship of a Match – for example: 4C (4th cousin) or 4C1R (4th cousin once removed), or 3Cx2 (double 3rd cousin), or 2C/2 (half 2nd cousin). So the shorthand ID is usually something like 36P/4C1R – a lot of information packed into a compact ID. And, given this shorthand ID, I can always repeatedly divide the Ahnentafel number by two to get back down to me. For example: 856M breaks down to 428-214-107-53-26-13-6-3-1 (me); which is on my mother’s father’s side. I can easily tell that other Matches with 214M and 53M and 13M MRCAs are all on this same ancestral line.
Use a Shorthand ID for CAs and MRCAs
36P/4C1R = the CA is Ahnentafel 36, Paternal side; the Match is a 4th cousin once removed
[22W] Segment-ology: Shorthand ID for Common Ancestors TIDBIT by Jim Bartlett 20190202