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GEDmatch interpretation

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  • GEDmatch interpretation

    I have had Y-DNA111 (and FF) tests carried out to try and find an unknown GGrandfather. FTDNA identified 1 possible Y111 match at GD7. I then uploaded to Gedmatch to see if there were additional matches and identified a very large number estimated GD4-5. I am an elderly novice struggling to understand what to do next and whether I should contact any of these as I have little to offer - I don't know potential surnames, other than my Grandfather's Birth details and where he lived in the UK. To contact them all is impracticable - how do I identify the strongest possibles? I have selected 2 people (who are tested as GD1 to each other) who both appear in my One-to-One List as GD4.6 as an example - both have no shared X-DNA segments with me. I have attached a pdf which may help someone more experienced to advise. Can anybody help?
    Attached Files
    Last edited by dagian; 13 December 2017, 02:34 PM.

  • #2
    Hello Dagian

    Some observations.

    I am not sure if this is a point of confusion for you, but GD = 7 for 111 YDNA has nothing to do with your GD of 4.6 at GedMatch. In fact, GedMatch never refers to a GD. The 4.6 is in a Gen column on One to Many or just referred to as 'estimated generations to the Most Recent Common Ancestor'

    So GD 7 meant you have a 104/111 match on the YDNA, which is pretty good but could be several levels of cousins away from you. For example, I have a 109 and he is a 5th. Your 104 might be closer but he might also be further away.

    On GedMatch, which is an Autosomal database like Family Finder, there is no Y analysis. You can list your Y haplogroup but its just for display. No effect on the results.
    Gen of 4.6 would be like this
    4.0 means gg gp in common, or 3rd cousin
    5.0 means ggg gp in common, or 4th cousin.
    4.6 implies a 3rd to 4th cousin with a gg gp or ggg gp in common.

    So 4.6 isnt remote but its not exactly close either. You are going to have a hard time working on a 4.6 without some clues. There is no reason to believe the 4.6 has any connection to your gg gf. Might even be on your mother's side. By using the "People who match one
    or both of 2 kits Updated"
    tool on the main menu, you might get some clues as to common relatives.

    Practically speaking, I think you need to concentrate on the matches below 4.0. It sounds like you may not have any. If so, I think you are at a stalemate for awhile. Not forever.

    I would recommend you buy an AncestryDNA kit while on sale now in Dec and try to find some gold in their 7 million member database. People above 100 cM. This is probably your best bet.

    And check back on Gedmatch once or twice a month to see if you got any new better leads.

    As far as a 0 on the X chromosome, that's normal and not a big deal. If you get a large match on the X, then work on it but even then, those are very confusing matches. You can sort the X column and see if you have any large X matches (like over 40 cM??).

    Maybe take a 6 month International subscription so you can search their database for your grandfather in the UK. Occasionally there are free days, but it might take more than a few days to thoroughly search.

    One last thing. Person A and B appear to be parent and child. Might even be the same person under two accounts.

    One last last thing. A new company called LivingDNA has started up and focuses on Great Britain. They are still very new and probably would not help much but as they expand their database and get more features up and running, they might help. You are trying to find British relatives in a basically American databases and while that could happen, its also means the cards are stacked against you slightly. This test is also on sale right now.
    Last edited by mabrams; 14 December 2017, 06:05 PM.


    • #3
      Many thanks mabrams,

      Things are now much clearer as you have explained in such a way that even I can understand. I did try to read-up on the subject but the more I researched the more confused I became. Simple explanations are the best - as you have provided. I rather stupidly mixed up GD and MRCA .

      I am a Member of Ancestry but did my tests with FTDNA as they offer a wide range of tests (particularly YDNA) which I believed would help me discover my Paternal line.

      Whilst it would be great to eventually discover the name of my GGrandfather, initially I was trying to determine what my Paternal Surname would be and then possibly join a Surname Group. My assumption is that the Match at Y111 would be a strong indicator of the Surname as it is within the last 4-5 generations. There were 3 other matches at Y67 with the same Surname. Using that Surname I created a new Tree at Ancestry and using a Paper Trail found a 'suspect' who was the correct age living very close to my GGrandmother in the UK at the time my Grandfather was born.

      GEDmatch does not offer Surname lists so it is not practical to contact all the matches to ask if they have the Surname I am seeking in their Trees. I suspect that the reason for the GEDmatch results is more to do with the fact that the 'suspect' was Irish. The matches are therefore likely to be a result of the mass emigration to the US/UK (particularly during and after the Potato Famine); many more would have tested in the US.

      I shall follow your advice regarding an Ancestry Test. Thanks again.
      Last edited by dagian; 15 December 2017, 05:14 AM.


      • #4
        I am glad my previous message was of some help to you.

        I think you are right that 111 matches can be a good indicator of your genetic surname over the last several generations. But a GD of 7 is a bit of a stretch, so 4 to 5 generations as you hope might also be a stretch. But certainly a strong possibility.

        You did right to test here as I think overall FTDNA is the best genetic genealogy company. But with limitations. And AncestryDNA has the super large database of 7 million perhaps 8 million by end of Dec. And many have decent trees. But the lack of any other tools is an extreme issue so you ultimately you have to combine AncestryDNA + FTDNA + GedMatch + others (23andMe or MyHeritage or LivingDNA) as each site has their own set of excellent features and frustrating limits.

        btw, if you get a BigY, on sale in Dec, you will get a free upgrade to 111. ($168 bonus)
        Last edited by mabrams; 15 December 2017, 09:48 AM.