Can Ancestry.com "ThruLines" prove lineage?

+8 votes
315 views

So, I had one line from a 2nd g.grandmother that produced NO DNA matches through Ancestry.com ThruLines. Her parents I listed were only my best guess. I substituted a new set of parents for her, and all of a sudden, I got 9 DNA matches!

My question is, what, if anything, does this prove? At first, I thought I was on to something. But then I read Ancestry's description of ThruLines, and it basically told me that the predictions were only as good as the trees we've constructed. That sounds like the new DNA matches I got might be misleading.

Bob S. 

WikiTree profile: Phynette Main
in The Tree House by Bob Scrivens G2G6 Mach 1 (18.2k points)
Deleted

9 Answers

+13 votes
 
Best answer
I've found that the Thrulines are only as good as other peoples' trees including your own. The best thing to do is to use them as a guide. If it matches the paper trail, then you are good to go. If not? Well, there is an error in someone else's tree. I would check out several videos about the topic online.

Good luck!
by Chris Ferraiolo G2G6 Pilot (300k points)
selected by Shanna Leeland
+11 votes
It might prove that now your tree shows the same ancestors as your matches' trees.  They might all be wrong, though, and all you've done is make yours consistent with the others. You need to review the documentation.  If no one has any and they've all just copied each other, I suggest you keep researching.

You might ask your matches to upload to GEDmatch so you can review your shared DNA information in more detail.
by Julie Kelts G2G6 Pilot (229k points)
I'm inclined to think you're right. Those online trees have a way of repeating mistakes. Even with Ancestry's "hints," you can easily go down the wrong path.
I have the same situation that Julie describes -  ggg-gparents, about whom we are very confident based on the paper documentation, with lots of cross-linking thrulines. But their parents are obscure.

The hint that thrulines gives you might be very valuable - if the new matches trace their ancestors back to the siblings of your confident ancestor couple. So now you can look for parents with a number of children rather than just trying to identify parents of your ancestor. It will never be "proof", but could be enough extra evidence to turn a "guess" into a "reasonably confident".

This includes researching the other matches' trees until you are confident they are correct.
+6 votes
This is a great question, as I'm only familiar with a very basic understanding of it, I'm not personally familiar with all the details behind it.

I do believe that the following example links do explain the Ancestry ThruLines fairly well...

https://support.ancestry.com/s/article/AncestryDNA-ThruLines

https://www.legacytree.com/blog/ancestrydna-thrulines

... But I do believe that you "may" be able to locate/obtain some better information/guidance if you ask this question within the following Ancestry Forum/Message Board specific to this topic.

https://www.ancestry.com/boards/topics.thrulines

Just a personal note/opinion in hopes that you may be able to obtain some better clarity regarding your question.

Good Luck!

~Brian Kerr
by Brian Kerr G2G6 Pilot (113k points)
+10 votes
It's a start, but doesn't prove anything.  How big are the matches?  If they're tiny, it's more likely that this is just coincidence.  If you look at the shared matches with each of those matches, do they overlap (match each other and maybe share other shared matches), suggesting a cluster descended from a common ancestor?  Dig into the paper trail and see whether there's support for the relationships.  

With that close an ancestor, you might be better off using cluster analysis to look for close (3rd-4th cousin) matches that you know aren't descended from your other great great grandparents, rather than relying on Thrulines.
by Lisa Hazard G2G6 Mach 9 (92.9k points)
+10 votes

Take a look at this discussion, I was right where you are and realized that all I was doing was to recreate and validate a bunch of unsourced lineages.

https://www.wikitree.com/g2g/944547/be-careful-with-thrulines-on-ancestry-com

by Robin Lee G2G6 Pilot (592k points)
+11 votes
I don't believe it proves relationship, but Thrulines can provide access to information that may not be apparent otherwise.  The 'relationship paths' point to other Ancestry users who share ancestors in my tree.  Tracing those, I can find the amount of DNA we share and a lead to their tree.  Not all are definite "yes" or 'no', but it helps to narrow the search.  I have so many matches that I easily overlook some--especially when our trees don't match exactly.
by Jo McCaleb G2G6 Mach 1 (17.3k points)
This has been my experience, too.  ThruLines has definitely given me some hints.  It's far easier to sleuth with hints, so I appreciate ThruLines for the most part.
+7 votes
No, they are just showing you other peoples' trees when you share ancestors. It's just a tweaking of their other similar features.

In fact, last week I found a thru line with a fraudulent lineage -- someone anglicized a German ancestor and gave her a Mayflower lineage. It's horrifying. I wrote Ancestry specifically about it to complain.
by Dina Grozev G2G6 Mach 4 (47.1k points)
Since so many people are currently desperate to find their Mayflower ancestor, they copy any tree that shows one. Thrulines tells me that I probably have one but it is always on a line that has been thoroughly disproven with extensive documentation. The more trees copying bad data, the worse Thrulines becomes. At least half of the suggestions I get from Thrulines are from bad data.
Researchers are accustomed to being careful about old trees, it's this DNA aspect that makes it dangerous by giving it false weight.

When I think about how much painstaking research that several people (including an author) along with myself have done on this particular family of German origin and then Ancestry comes in with this, it makes me terribly sad.
+4 votes
In terms of Ancestry, I use ThruLines quite sparingly compared to the 'Shared Matches' when I'm viewing results.  I've found that I and certain other people all match each other and have a given surname/location in common-I've definitely found cousins that way.  ThruLines helps me pick possible matches to investigate and then I proceed with running the shared matches query.
by K. Anonymous G2G6 Pilot (103k points)
+4 votes
I've gotten some good evidence out of it. Also some that not correct. Think of it as another source of possible evidence & check it over thoroughly. The other new feature, theory of relativity, has been even better. It will tell you of possible relationship paths EVEN for people that have unlinked trees. This could save you a lot of wasted time contacting people that are of no use to you.
by

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