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Ethnic Makeup in Family Finder vs. Big Y's Block Tree. Is this a bug?

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  • Ethnic Makeup in Family Finder vs. Big Y's Block Tree. Is this a bug?


    What's the difference between "Ethnic Makeup" in Family Finder and Big Y Block Tree? Both come from autosomal DNA. I have < 1% Native American in Family Finder and 25% in the Block Tree of my Big Y test. ??? Could someone explain these two numbers for ethnic makeup. Thanks
    Last edited by blbertram; 27th June 2019, 06:29 PM.

  • #2
    I'll take a shot at this, but am no expert. First, both do not come from autosomal DNA.
    • Family Finder - the ethnicity predictions come from comparing your autosomal DNA to reference populations, with the results yielding estimates in percentages, by population groups. Family Finder is used to find relatives with a common ancestor generally from 4 to 6 generations ago.
    • Big Y Block Tree - Big Y is, as the name implies, a test of Y-DNA; specifically, the SNPs. The ethnicities you see in your matches in the Big Y Block Tree are self-reported by those matches. In other words, it is what each match knows of their ancestral origins. The common ancestors, while they may be within recent generations, may also be much further back, possibly hundreds or thousands of years before a genealogical timeframe.
    Family Finder is broken down by percentages, based on algorithms and reference populations used by FTDNA. I assume that you determined your 25% figure in the Big Y Block Tree by adding up your matches that claim NA ancestry, and seeing how much percentage of all your matches that was. It is a quantity of your current matches; if more men test in your haplogroup, and are in your subclade, that percentage may change.

    In your case, your autosomal results show that only <1% (considered a "trace" amount) seems to match known Native American DNA. It may possibly represent a Native American ancestor you had, but could be a 5th great-grandparent or greater. But your 25% in the Big Y Block Tree is based on what your matches' have self-reported, and could possibly have been from another ethnicity. It is possible that, if your <1% NA in autosomal is not just noise, it may have been that your early direct paternal line ancestor was NA.

    On the other hand, particularly with the label "Native American," some people misunderstand the use of that terminology for their ancestry, mistakenly using the term "Native American" (which is actually indigenous peoples in the Americas before Europeans) for "native" American, meaning people who have lived in the Americas for many many generations, but whose ancestors were colonists or settlers. Some people who do not know where their earliest immigrant ancestor came from will say that they are Native American, when they should say "United States." We see this most often in the Ancestral Origins section for Y-DNA STR testing, or mtDNA.

    What is your Y-DNA haplogroup? I believe that the only known Native American Y-DNA haplogroups are some subgroups of haplogroup C, and some in haplogroup Q. Also, R1 may be another NA haplogroup, but only specific subclades. You may want to contact the project administrators, if you have joined a Y-DNA haplogroup project, to confirm that the SNPs associated with your 25% NA matches are truly known to be associated with Native American Y-DNA haplogroups.
    Last edited by KATM; 27th June 2019, 11:09 PM.

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    • #3
      Thank you Katm

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