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Old 14th September 2017, 04:25 AM
David Potter David Potter is offline
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Join Date: Jul 2017
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Confusion with My Origins result

Hi Forum

I'm struggling to understand a My Origins result for my son.

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Myself, my wife and our son have all tested using Family Finder and for myself Y-DNA37. When using the My Origins mapping. Mine and my wife show 98% European and trace origins but none of these trace origins are Scandinavian. Family Finder Identifies us three as Parent/Child relationships. So why does my sons Origin makeup state 30% Scandinavian when there is zero Scandinavian in his parents origin makeup?

Thank You
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Old 14th September 2017, 10:31 AM
John McCoy John McCoy is offline
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Short answer: because the algorithm doesn't always work very well!

You are correct in thinking that inconsistent results, where a child is estimated to have a strong "ethnic" component that neither parent has, should not occur.

There is a discussion of this point in the "white paper" about estimating ethnic origins on Ancestry's web site -- they say they gathered some statistics showing that their latest ethnic origins algorithm performed better (produced fewer inconsistent results for parent/child trios), but they didn't give specific results. There are a number of other ways to attempt to validate these algorithms, but, for this situation, there is really no foolproof external standard by which we can objectively measure accuracy (as opposed to consistency).

By my reckoning, there seem to be 3 major difficulties:

1. "Reference groups" (groups of modern DNA samples that are supposed to represent historical populations of various "ethnicities") have to be inferred (guessed at), with no way to assure that they actually reflect the genetic diversity of a particular long-dead "ethnic" population.

2. Because of recombination and the random assortment of chromosomes, the DNA contribution from some of your ancestors will be higher than expected, and for others, lower than expected or even non-existent, with the result that the actual percentages of the various "ethnic" components of your DNA cannot be expected to match the percentages that are computed from your genealogical pedigree.

3. Whether from the selection of SNP's used to determine ethnic origins in any particular algorithm, or from the way they are scored, logically inconsistent results are frequently obtained. I think this is a mathematical, methodological problem that it should be possible to overcome! However, if there were an easy solution, I would expect someone would already have worked it out.
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Old 16th September 2017, 11:35 AM
Frank Kelch Frank Kelch is offline
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David, you might want to consider uploading your raw data to MyHeritage, GEDmatch and DNAland (it's free)... None of the ethnicity calculators are perfect, but you may get a better understanding of your ethnicity by comparing multiple results. And of course, it's always a good idea to follow your paper trail with traditional research.
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Old 9th October 2017, 10:42 AM
David Potter David Potter is offline
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Join Date: Jul 2017
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Confusion with My Origins result

Hi Both, really sorry for the late reply. I thought I would receive an email when someone had replied - didn't get anything so just checked in and saw your replies. Thank you. I did upload my DNA to MyHeritage and I now see a similar makeup to my son. So now I have uploaded his to MH in the hope that will confirm both of us have Scandinavian origins. We'll see. But clearly the FTDNA algorithm leaves room for improvement.

Kind regards

David Potter
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