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DNA Footprint?

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  • DNA Footprint?

    Newbie here looking for advice/guidance please. I have never seen this question asked before and don't even know if it is feasible or how it might help but here goes...

    I am on the hunt for my unknown Paternal Grandparents. Although I have proven 1st and 2nd cousin Maternal DNA matches, unfortunately apart from myself I have no proven Paternal matches. I do have matches who do not match my known Maternal matches. The highest at 396 Cm and another at 248 Cm. They also match each other. As is usual for me in my research they were both adopted and know nothing of their biological parents. My question is this -

    Can I use these matches, and further matches that triangulate to them, to build a much larger Paternal DNA footprint that I can then use to compare other unknown matches to? Perhaps using DNA painter?

  • #2
    Your two mystery matches are close enough to you (on the order of first cousin once removed or half first cousin) that you may be able to narrow the possibilities. There are only so many family trees that could generate relationships this close, particularly given that they don't match your maternal matches. For example, if you assume that your mystery matches are from you maternal side, are there any possible family trees that could lead to the result that both of them don't match you or any of your maternal relatives? (It is very rare to find a non-match for any relationship closer than third cousins.) Are there any segments that you share with your two mystery matches that don't match a segment at the same location that you share with one of your maternal relatives? You may have enough evidence to prove that your mystery matches are indeed from your paternal ancestry.

    The next step would be to search for shared matches. Ideally, you should try to identify triangulation groups, such that all kits within each triangulation group share the same segment with all other members of the group. While this can usually be done for at least some matches and their individual matching segments, identifying the common ancestor responsible for each segment is often far more difficult, because the family trees posted on DNA web sites are often not very informative. But the genetic evidence needs to be combined with traditional genealogical research (the paper trail). You and your mystery matches may be able to combine your efforts and narrow the possibilities even further. Sometimes searches like this take several years to untangle, but there are many success stories. Don't give up!


    • #3
      Falconer, in addition to John's great suggestions, you could load your raw data from FTDNA to MyHeritage and GEDmatch. Also, 23 and Me, if they will take it. That gives you exposure to other matches/databases. Be sure to do your due diligence on Gedmatch since they may do sharing with law enforcement. Ancestry does not take dna transfers although they have trees, albeit in diminishing numbers these days.

      MyHeritage has a built-in triangulation which is neat.


      • #4
        Thank you John, I understand (I think!) Unfortunately one of my close matches is only listed on Ancestry. Bot the other is on Ancestry, MH, FTDNA and Gedmatch which helps. There are 8 matches on Ancestry that match both of them and myself, but unfortunately no useful trees. Also no indication of ages of them either which may have helped...


        • #5
          Biblioteque, I have uploaded my raw DNA to MH. FTDNA and Gedmatch but only have one large non-maternal match. The same one that is on Ancestry. All others are below 30 Cm...


          • #6
            Falconer, you mention nothing but autosomal DNA, so if you are a male, you might consider Y testing for yourself. We have men in our surname project who found enough clues from Y matching to narrow research paths along groups of surnames and haplos to bolster suspicions of patrilineage they already had (two men), or to look for previously unsuspected clues (two individuals and two brothers and a known cousin). Your direct male inheritance is not subject to appreciable recombination, so this would be a tool in your research for your paternal grandfather, with no issue of "phasing" or centimorgan "distancing" since this is a male-to-male inheritance. I will also add that several men in our project do not use our surname of interest, but came to my attention (or I came to theirs) by Y matching alone.They now feel a bit closer to solving their mysteries by at least being able to filter out males who do not share their haplogroup.

            But again, this only helps if you are a male, and most of our men tested for 67 to 111 Y-STR or to BigY, not the least expensive routes. If you carry the R haplogroup, then you might have a huge pool of possibilities to narrow down, but if you spring for the BigY700, your terminal SNP might put you on a branch with some useful matches. It sounds like a long-shot for the money involved, compared to autosomal that you can xfer to other databases, but I mention it in the absence of any hint that you have explored that route. And there are two databases, FTDNA and YFull, that could hold such a clue.
            Last edited by clintonslayton76; 27 April 2020, 05:22 PM.


            • #7
              Thank you clintonlayton76, I am male and neglected to say I have taken a FTDNA 67 marker test. I have no matches above 12 markers. I have 18 matches in total, 10 of which have Latino surnames (I show only European ethnicity) The others of course may be useful if I knew for certain my Grandfathers surname. I do have a name he gave on my Father's birth certificate but I suspect this is not correct as out of many thousands of autosomal matches I have only 6 very distant (6 Cm) matches with that surname in their tree, and none were born in England.


              • #8
                I will admit that my suggestions are not as likely to lead to an identifiable grandfather, and expanding your Y results will be expensive compared to using autosomal samplers, but mentioned it for completeness, because you are carrying your unknown grandfather's Y chromosome and any matches with Y STR or SNP samplers might be years away, if ever. But it does happen that such identifications are possible. Thanks for clarifying.