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African dna

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  • #16
    As one point of reference, I've got a creole ancestress 6 generations back, and the african shows up as 2.75 - 3% where I would expect it to be about 1.5% (based on 1/2^6 * 100)

    Once people's geno2 results start coming back, and if you've got the money to satisfy your curiousity, it might be worth taking a look at them to see if they might address this for you.


    • #17
      I also have a small percentage of African dna although my paper trail gives no indication of this. Interestingly enough, I have tested three half siblings and just got the results back from Dr. McDonald for the last sibling. The first two half siblings did not show any African dna, but this last half sibling does. The tricky part of this is that I don't have any full siblings, and this last half sibling has a different father than the other two. So I have to find some way to determine if this comes from our mother's line, which we share, or if by some coincidence both of our fathers have hidden African ancestry that shows up for both of us on the same chromosome. We both have portions on chromosome 15. My half sibling's segment on 15 is longer than mine, but I have two segments that overlap her longer segment. I have also tested my maternal grandmother, again she is a shared grandmother amongst all of the siblings, and her results do not indicate any African ancestry. I would really appreciate any tips or comments.

      Here's my discussion from Dr. McDonald:

      Most likely fit is 98.6% (+- 0.6%) Europe (all Western Europe)
      and 1.4% (+- 0.6%) Africa (various subcontinents)

      The following are possible population sets and their fractions,
      most likely at the top
      English= 0.975 T-Ethiop= 0.025
      English= 0.976 A-Ethiop= 0.024
      English= 0.981 O-Ethiop= 0.019
      English= 0.986 Maasai= 0.014
      English= 0.989 Bantu Ke= 0.011
      English= 0.990 Mandenka= 0.010
      English= 0.990 Yoruba= 0.010
      English= 0.990 Bantu So= 0.010
      English= 0.992 Biaka Py= 0.008
      English= 0.993 San= 0.007

      Pretty simple ... African is not well-defined.

      Here's the discussion for my half sibling:

      Most likely fit is 97.7% (+- 0.4%) Europe (all Western Europe)
      and 2.3% (+- 0.4%) Africa (various subcontinents)

      The following are possible population sets and their fractions,
      most likely at the top
      English= 0.978 Mandenka= 0.022 or
      English= 0.979 Yoruba= 0.021 or
      English= 0.979 Bantu So= 0.021 or
      English= 0.978 Bantu Ke= 0.022 or
      English= 0.982 Biaka Py= 0.018 or
      English= 0.977 Maasai= 0.023 or
      English= 0.973 O-Ethiop= 0.027 or
      English= 0.970 A-Ethiop= 0.030 or
      English= 0.985 San= 0.015 or
      English= 0.970 T-Ethiop= 0.030

      However, the African might be less, like 1%.

      Any ideas? I did ask Dr. McDonald whether he though my African percentage was real or potentially noise, since it was below 2%. He stated that it was likely real, but not well defined in terms of population.