ThruLines Has X-ray Vision

A Segment-ology TIDBIT

AncestryDNA’s new ThruLines automatically finds Common Ancestor(s) – out to 5xGreat grandparents.

AND, because AncestryDNA can also see the Private Trees, it can find Common Ancestors you cannot see – it’s like ThruLines has X-ray vision! If your Match’s Private Tree is searchable, it will even show you the path to the Common Ancestor (otherwise it will show Private for each generation back to the Common Ancestor). This is a very powerful feature. Many of us complain about all the Private Trees.

Well… now ThruLines looks right into them for us and determines our Common Ancestor(s). ThruLines works to find these Private Matches even when they have small Trees, but have an Ancestor who is also in your Tree as a descendant of one of your Ancestors (see previous post about adding children and grandchildren). If you think you know how a Private Match might be related to you (say, by finding several Shared Matches, all on one of your lines), try adding some more descendants in that part of your Tree and wait a day or two. This also helps in developing larger groups of Shared Matches and identifying more Matches in Clusters.

Use ThruLines to find Common Ancestors with Matches who have Private Trees!


[22AI] Segment-ology: ThruLines Has Xray Vision TIDBIT by Jim Bartlett 20190729

13 thoughts on “ThruLines Has X-ray Vision

  1. Pingback: segment-ology

  2. Pingback: AncestryDNA and Other Goodies (a test covering this will be given at the DNA Sig) | Monterey County Genealogy Society

  3. Gary, I would (and have) tried this tactic. I would also recommend anyone doing this to back out (delete) their trials in as short a period of time as is reasonable. In other words don’t leave guesses hanging out there – others tend to pick them up for their own Trees (which is not at all helpful).


  4. As a genealogist since 1967, in the dark ages without a computer, this is the best improvement since DNA came into play with our research!


    • Helen, I didn’t get started as a genealogist until 1974, and I remember those days – writing letters and visiting courthouses and Archives. In 1978 I got a job with the Smithsonian, and spent my lunch hours scrolling microfilms at the Archives or searching through the stacks at the DAR. I started a DNA project in 2002 and I’ve been a genetic genealogist ever since – having tested at all the major companies. I think this is still the frontier, and we are still learning… I agree that ThruLines is putting the computers to work finding all the matching info – like it should be… Thanks for your comments. Jim


  5. What are your thoughts about exercising ThruLines using hypothetical ancestral connections?

    My paternal GGF was adopted and went by the surname Hamilton. YDNA shows his (or his father’s) surname was Gilliland and that we belong to the relatively small Gilliland Group 2. Nearly all of my 4th-remote cousins with Gilliland Group 2 ancestry descend from a TN patriarch James Gilliland 1774-1815. I have experimented by placing James’ descendants of an appropriate age as my GGF’s father. ThruLines is extremely accommodating in coming up with theories about cousin connections to descendants of James Gilliland. Some I am able to verify but others seem to be there just as a slight possibility or even a crazy thread that can be easily dismissed.

    Any thoughts about making this approach helpful vs. just creating more rabbit holes?



    • Hi Gary:

      Did you ever receive a reply to this post?

      What you are doing sounds like something that might be useful in my own research, as I try to determine who the biological father of my grandfather was (certainly, not the man whose name is on my granddad’s paperwork). Using DNA shared matches, I’ve narrowed down the field to some families whose surnames keep showing up in my own and my paternal cousins’ matches in Berks County, Pennsylvania, but I have not yet figured out how someone there came into contact with my great-grandmother in Somerville, Massachusetts, nor have I yet determined a most recent common ancestor.

      I’ll be interested to know what Jim Bartlett has to say about your approach. Thank you for your question.



      • Gail,

        I answered this post. As part of my Brick-Wall post on CUMMINGS, I did add my hypothetical John CUMMINGS ancestor, and it worked out. I’ve tried some other guesses and they did not work out, so I’ve deleted them. Jim


      • Hi Gail,
        I hadn’t noticed your request until now. As Jim notes he did reply. I haven’t had any breakthroughs using this technique. I rotated through about 10 different potential ancestors for my GGF. Usually they showed up in Thrulines in 2-3 days but sometimes it took at least a week. These are my takeaways:
        1) No breakthroughs on my GGF brick wall.
        2) This is a pretty amazing tool. I can tell how well the concept works by its ability to confirm what I already know about other relatives.
        3) On the flip side, although Thrulines found a way to connect many of my matches who also have a Group 2 Gilliland in their backgrounds, nothing so far has led to a right place/right time candidate (mostly due to the lack of corroborating evidence/additional matches with that person’s other relatives).
        4) Thrulines will do it’s best to make you happy and keep you engaged with real or completely bogus guesses. Take care to evaluate the guess connections. There is often only one tree that ties together 4 generations from the 1700s or 1800s with dotted line boxes all the way down to your present day match.
        5) All in all a fantastic tool as long as you do your due diligence to verify when the lines look shaky.


  6. Thanks for posting on Thru-lines. I’ve been using it to help an in-law find their cousins. Not only does it find possible common ancestors, but it presents the records supporting the relationship. Its made it possible for me to untangle some really tangled family and it hugely leverages my FAN approach. Hallelujah!
    I would think this could be valuable in annotating your spreadsheets – the best of the segmentology and approaches – inferring the segments from the relationships? Or not.


    • Anadygirl,
      I agree. I divide my whole effort/objective into 2 parts – the DNA part (mapping shared segments) and the genealogy part (finding Common Ancestors within each TG who agree with each other on the same ancestral line). My spreadsheet lists all of the shared segments and Triangulated Groups, and I note the Common Ancestors for all the Matches where known. I’ve been adding Cluster numbers which helps confirm the TGs. The trick is figuring out which TGs (segments) go with each ThruLines Common Ancestor – that’s happening primarily through the AncestryDNA Notes. And begging AncestryDNA Matches to upload to GEDmatch. Jim


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