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How far is recent ancestor for 12 marker exact match

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  • How far is recent ancestor for 12 marker exact match

    If i have an exact 12 marker match with someone, how far the common ancestor would be?

    https://www.familytreedna.com/faq-markers.aspx

    According to the above site, it means that there is a 95% probability that the ancestor is no longer than 29 generations and by 29 generation i guess they mean 1000 to 1500 years. Is this assessment correct or not​​​​​​​

  • #2
    I wouldn’t pay much attention to a 12 marker match, focus more on 37 and up.

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    • #3
      hussainr565, it is best to post each of your questions only once, in the most appropriate sub-forum for each question. When you post the same question in multiple sub-forums, it will be hard for you to keep track of who replied in which of several of them. It is also hard for other people to keep track, in order to help answer your questions.

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      • #4
        It's not reliable. A resolution of 12 markers is just far too low to place any confidence in. I have literally hundreds of exact 12 marker matches with people from a subclade that I don't share a common ancestor with in the last 5,000 years. 12 marker matches mean almost nothing.

        I wouldn't start taking STR matches seriously until you get into the 67 marker or higher resolution territory. Which is frustrating for me because I don't have any matches closer than 25 markers, and unfortunately their SNP statuses still say that I can't be related more closely to any of them than 3,000 years ago. Even 37 marker matches can be highly ambiguous.

        That doesn't stop me from hypothesizing on possible relationships based on 37 marker haplotypes where I don't know the person's subclade, though. Not because I think they're reliable, or that I'm getting useful information from them, but because I'm so desperate for any kind of information that I'm scraping the bottom of the barrel. I know I'm wasting my time, but there's nothing else for me to do.

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        • #5
          I don't know for a fact, but my guess is that the methodology they're using to calculate the probabilities associated with these genetic distances is based on the distribution of mutations from a common ancestor. Which is a wrong, almost circular kind of reasoning, assuming that all mutations since the common ancestor are visible, which obviously is not the case for very remote common ancestors, due to convergent mutations, back mutations, etc. If it's not exactly a circular kind of reasoning, it's at least highly misleading, and the calculator should display appropriately qualifying language.

          They should be using the estimated distribution of allele counts for the respective loci among the whole population worldwide. I would expect the result for such low-resolution tests as 12 markers to return some very discouraging information, but at least it would be an accurate reflection of the odds surrounding the relationship.

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          • #6
            If you and someone else have a (12, 0) Y-DNA match, you can be confident that both of you are human. A match of (12,0) is not worth worrying about.

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            • #7
              The issue is that all I have are 23 12 marker matches and I have gone for a BigY test. The results are out till Y-111 and so far all i got are 12 marker matches which is a little frustrating

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              • #8
                Originally posted by hussainr565 View Post
                The issue is that all I have are 23 12 marker matches and I have gone for a BigY test. The results are out till Y-111 and so far all i got are 12 marker matches which is a little frustrating
                Would I be correct assuming that you have a relatively uncommon haplogroup (in comparison to the rest of the FTDNA database)? The demographics of the FTDNA database are heavily American leaning, and many of those trace their ancestors to UK & Ireland.

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                • #9
                  Originally posted by spruithean View Post

                  Would I be correct assuming that you have a relatively uncommon haplogroup (in comparison to the rest of the FTDNA database)? The demographics of the FTDNA database are heavily American leaning, and many of those trace their ancestors to UK & Ireland.
                  I guess so. My Haplogroup is L-M20 which is kinda rare when we compare with Americans.

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                  • #10
                    Originally posted by hussainr565 View Post
                    The issue is that all I have are 23 12 marker matches and I have gone for a BigY test. The results are out till Y-111 and so far all i got are 12 marker matches which is a little frustrating
                    I have a litlle over a dozen GD0 matches at 12 markers(most are from a clan of Kuwaiti's who share a roughly 5,000 year old common ancestor with me), a few dozen are [email protected] markers(in a common project so I can see them, and they are overwhelmingly from Europe as expected), a solitary match at 25 markers(aside from my father), and another different match at 67 markers. Neither one of those two have responded to contact attempts.

                    I can certainly understand the frustration.

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