A Segment-ology TIDBIT
Although this Segment-ology blog is focused mainly on understanding and using DNA segments, I’ve also tried to look at the genealogy part of the genetic genealogy equation. We need both genealogy and DNA tools. AncestryDNA has some good genealogy tools that help us with our DNA Matches.
One of the powerful tools is ThruLines. Ancestry uses this tool to analyze your Tree, each Match’s Tree, and every other Tree in its inventory to try to build links to a Common Ancestor (CA) for you and each Match. This includes finding CAs with private, but searchable Trees, and with small Trees that may have only a Match’s parent or grandparent. In all cases Ancestry will try to fill in any gaps between the CA and you and/or your Match. The result is a diagram showing how you and the Match are related through a CA, along with reference material to indicate how they determined any generations they used to fill in a gap. This is a powerful tool, which can be used in a variety of ways.
I’ve written about:
- How ThruLines Works, here.
- Helping ThruLines help you, here.
- ThruLines Xray vision (into private Trees), here.
- Adding ThruLines info into Match Notes, here.
- Using ThruLines and Shared Matches to form Clusters, here.
- Using ThruLines to Extend the MRCA of a group, here
All of these posts use Matches who share DNA segments with you, and ThruLines adds the added dimension of genealogy – using the power of Ancestry’s huge database of Trees. ThruLines usually uses multiple Trees which are in agreement. This is a good, easy, place to start – a good hint – but like all such “hints” you should validate the result. Yes, some of the Trees are flawed, but most are not. Based on my 45 years of genealogy research, I’ve found ThruLines to be correct about 95% of the time.
This post is about another way to use the power of ThruLines – checking on a suspicious branch of your Tree. Suppose you have a Tree and have been documenting Matches who have Common Ancestors with you. And you notice that one branch of your Tree isn’t getting as many Matches as you expected. It may be because the branch is one that recently immigrated to the US; or because the Ancestors in the branch had relatively few children. Both reasons would tend to reduce the number of Matches from that branch. But if you’ve ruled those reasons out, what’s left? Well, the elephants in the room are a non-biological parental relationship in your Tree (an NPE or MPE) or faulty genealogy research.
One way to check a suspicious branch is to use ThruLines, as follows:
1. Determine the Ancestor who is the base of the suspicious branch – use your judgment.
2. Click on the child who is your Ancestor
3. Open that (child) Ancestor’s profile page
4. Open the Edit tab (top right)
5. Select Edit relationships
6. Click on the X next to the suspicious parent(s) – one or both
This will remove the suspicious branch from your Tree. It will also preserve all the work you’ve done on that branch, and at any time you can easily go back to the child (#2 above) and add the parents back in using the Select someone in your tree option (just type in the names you had before and select them).
After you’ve removed the suspicious branch, just wait a few days. ThruLines will try to find Matches who are cousins from this line and will identify Potential Ancestors the fill in any gaps. This works out to the 6th cousin (6C) level – your 5xGreat grandparents. If ThruLines identifies Potential Ancestors who were the Ancestors you originally had – well nothing lost (but be sure to use the Select someone in your tree option to get back the branch as you originally had it). If ThruLines identifies alternative Ancestors – well then, you’ve got some work to do to understand more about those Ancestors and decide which Ancestors to use. Remember the ThruLines version is just a “hint” – it’s still up to you…
What I would do is accept the ThruLines Potential Ancestors (later, they can always be deleted or removed from the Tree with Steps 1-6 above) and see if I got a more ThruLines Matches than I had before. If so, these ThruLines Matches would have Trees that should be reviewed for additional evidence. My go-to evidence is the census records if they are available for these new Ancestors – are the times and locations appropriate? At this point, this is mainly a genealogy exercise, although a review of relationships and Shared cMs should also be done.
This is yet another way to use the power of ThruLines. It’s not guaranteed to work, but it does give you a quick and easy look into the huge Ancestry inventory of Trees for potential alternatives.
[22BB] Segment-ology: Do You Have a Suspicious Branch in Your Tree? TIDBIT by Jim Bartlett 20210928