Gedmatch and the X

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That makes sense. Thanks. I'll tell them.

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A friend of mine and her daughter (they've tested with 23&me and FTDNA) have a query. They are both matched with another party autosomally (the mother has 40.5cM and the daughter 38.8cM affinity totals), but only the daughter is related on the X (she has a common chunk of 11.8cM with the third party,...

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Understood. In any case, the principle that a parent cannot pass on more than he or she has applies....

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Gedmatch uses Dienekes' nomenclature. "West European" "East European" "Mediterranean" etc. I assumed that if the total "West European" in a particular chromosome, say chromosome 5, from the tested mother was 40% (Gedmatch analysis) and 50% in the offspring in...

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I am assuming of course that the other parent is unavailable for testing. The answer would seem obvious to me, but in these matters many apparently obvious things may not be. Hence the query....

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Is it correct to assume that if an offspring has 25% of a particular value, say "West Asian", on a given chromosome, while a tested parent has 5% "West Asian" on the same chromosome, then the excess percentage (and perhaps more) must have come to the offspring from the other par...

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Just to complete things, here are the three McDonald X paintings (grandmother, mother, granddaughter, i.e. 3 generations)

It looks as though what occurred was possibility 6 (with a variation?). The granddaughter gets her ME from her father's mother (there is nothing in her mother or maternal...

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Thanks a mill for this excellent clarification! I'll muse over it and see how it applies to my case.

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I was wondering because I found a 1998 article by Mahtani and Willard which claimed that in the area straddling the X centromere the rate of recombination was extraordinarily slow (8 to 20 times slower than on the rest of the chromo). If their findings were still acceptable this might suggest a beginning...

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Thanks. Nothing yet. I'll keep an eye out. Maybe you could give poor Saud McDonald's working address. That's what I tried to do....

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I registered, was apparently accepted, and tried to post but was unable to. Maybe I missed something....

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Thank you Tick and Matt. This is very useful and important information.
But my initial question was actually a little different. Let me rephrase (and I ask for your indulgence). Given the fact that this "South Asian" stretch appears at exactly the same spot in three continuous generations...

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I meant stepdaughter not mother in law. Corrected this. Sorry for the slip....

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I'm wondering if there is any way of calculating the age of a particularly sticky sretch around the centromere of my mother in law, my wife, and my stepdaughter. It is the same size in all three cases. It is securely "South Asian" as per Dr. McDonald's very cautious analysis. None of them...

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Is this the final consensus then: dna-forums is "gone with the wind"?