Subtitle: Teamwork in Practice
In my last blogpost about my ancestor Wilson BROWN, I hinted at a large group of Shared Matches to a Thomas BROWN b 1773 (m Nancy LITTON). Over 2,000 people have this Thomas in their Trees at Ancestry. After some collaboration, I was given access to the DNA kit for the person named MATCH in the diagram below [credit to Allen Brown]. I wanted to look at the ThruLines Matches for MATCH. Well… it turns out MATCH has 756 ThruLines Matches from Thomas BROWN b 1773, spread over 7 different children – just WOW! I looked at 276 of them, spread over 5 different children (not including MATCH’s direct ancestor). I clicked on each Match name to see if I was also a match to that person. Drumroll…. 28 of them were also DNA Matches to ME. So, using this information, how is Thomas 1773 related to ME?
Diagram of descent from James 1705 to ME and descent from Thomas 1773 to MATCH:
Remember the rough guidelines that true 2nd cousins (2C) will match 100% of the time; true 3C will match 90% of the time; true 4C 50%; true 5C 10%; and true 6C 2%? My little exercise resulted in ME matching 28 of 278 given cousins identified by ThruLines for MATCH. This is right in line with our expectation for a 5C! In the diagram above, Thomas would most likely be the son of Wilson, rather than a nephew (which would result in a 6C relationship between ME and MATCH). Note: we had already determined that the James BROWN 1705 line and the Thomas BROWN 1773 lines were both in Group 40 of the BROWN Y-DNA Project.
Maybe this is a fluke. I’d like to find another Match descendant of Thomas BROWN and see if I have the same ballpark results. Also, I’m still reviewing all of my AncestryDNA Matches with a BROWN Ancestor to see if there is another firm group (or Cluster) of BROWNs, so I can see if they also might descend from Wilson BROWN. Spoiler alert: I do have a very large (100 Match) Cluster that I have linked to my Triangulated Group [06F36] – so I’ve used [06F36] to tag my AncestryDNA Matches in that Cluster. As it turns out, virtually all of the Matches I have under Thomas 1773 are tagged [06F36] – another indication of the power of Clusters. I can now really dig into the other [06F36] Matches (tagged at AncestryDNA and in the [06F36] Triangulated Group with 284 Matches from 23andMe, FTDNA, and MyHeritage) to find their BROWN ancestry.
James BROWN c1705-1776 [see diagram above] left a Will naming 16 children. Other than the given names, there are very few records to tie the surviving children back to James [we are dealing mostly with burned out counties in Colonial Virginia]. Very few on-line Trees are tied back to James. However, we have found families with the same given names as the children. Isham BROWN is an example – same given name, but no records to link him to James, just a first name. But there are 2 descendants of Isham who are in Group 40 of the BROWN Y-DNA Project who claim Isham as their Most Distant Known Ancestor. Eake BROWN is a fairly unusual given name, and we are finding some records and descendants for him – looking for a living DNA Match… In his Will James named son George and George’s sons George and Archibald – two men in BROWN Group 40 claim a George and an Archibald (independently) as their Most Distant BROWN Ancestors… Theoretically we should be sharing about 2% of our cousins at the 6C level. Yes, it’s a stretch, but it’s doable. With virtually no good records, it might be the best avenue we have for linking these lines.
If enough folks try this process, we might get enough data to build probability curves and averages for the percent of shared cousins at different cousinship levels – a parallel to the Shared cM Project.
1. If you and a DNA Match can share your lists of Matches from a potential Common Ancestor, percent of Match overlap may indicate the cousinship level.
2. This takes work and time – I used it as a last resort, when my Ancestor left no records of children.
3. This is best done at AncestryDNA, with ThruLines, and therefor limited to 6C relationships, or closer.
CODICIL: In my excitement here I have presumed [06F36] is a BROWN Cluster or Segment. Not necessarily! I have concluded that [06F36] goes back to the Wilson BROWN couple – that [06F36] segment could have come from or through either Wilson OR his wife. It’s a 50/50 probability either way. I must do a lot of other analysis to figure that out.
[23_98Mb] Segment-ology: Percent of Shared Cousins Indicates Relationship by Jim Bartlett 20230315