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Common Ancestor question

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  • Common Ancestor question

    If you have 3 matches who overlap on a particular chromosome and you have identified a common ancestor between 2 of them, does that mean that the 3rd likely shares the same ancestor?

    For example here is what I have on Chromosome 4. Here are their starting points, ending points and shared Cm, respectively:

    > > > Match A 105191506 136261472 24.41
    > > > Match B 105191506 114597377 9.6
    > > > Match C 106489740 136261472 23.85

    I have identified the common ancestor between B (5th to remote
    relationship) and C (3rd to 5th relationship) as William Teague, 1693-1775. As for A (2nd to 4th relationship), the line that looks like it may be connected dead ends around the mid-1800s and I cannot connect him to the Teagues.

    Thanks in advance for any insight into this!

  • #2
    I should also add that we all match each other...

    I double-checked using the In Common With function.


    • #3
      Based on the length of matching segments, your MRCA with A and C are of the same generation. Your MRCA with B is 1.5 generations earlier. I surmise that A, C, and you are of the same generation. B is either one generation older than you or one generation younger. You must determine which is the case. Whichever it is, your MRCA with B may be the grandparent or parent of the MRCA with A and C.