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  #1  
Old 4th June 2018, 01:32 PM
Woody1 Woody1 is offline
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X-Match not in common with?

I have been trying to identify the ancestors of my mother's paternal grandmother for a long time. I'm now working on a strategy of using x-dna matches to try to narrow the search to people who might be matches to this great-grandmother of mine.

FTDNA has tests for my mother and for her brother (my uncle). My thinking is that my mother has one complete x chromosome inherited intact from her father and one re-combined x chromosome inherited from her mother.

Her brother, on the other hand, will have no x chromosome from his father and one chromosome from his mother.

So my mother will likely have inherited one x-chromosome passed from her maternal grandmother, while my uncle should not have any x-dna matches from that maternal grandmother. I want to find x-matches to my mother that are not in common with my uncle.

Here's my question:
1. Is this a valid approach?
2. Since my mother has one x chromosome from her grandmother, is there a way to tell whether someone matches to that chromosome or the one inherited from her mother?
3. Is there a technique or tool I can use to make this easy to do? My mother's kit is uploaded to GEDMatch, but my uncle's is not. What would be the best approach to figure this out?

I have looked at chromosome analyzers on FTDNA, GEDMatch and DNAGedcom, but I'm having a hard time working it out. Is there a better way to do this?
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  #2  
Old 5th June 2018, 04:00 PM
Fern Fern is offline
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I don't use X matches, because all mine are very weak.

I recently found the parentage of my father's maternal grandmother through my non-X matches - and all except one were at FTDNA. Two turned out to be 4C1R, one was a 4C, and another at Gedmatch was a 3C1R. More cousins showed up after I made contact with one of the 4C1Rs (the other 4C1R has never answered emails).

It helped that all the matches had trees posted ... and also that I'd done the "paper trail" for my great-grandmother's parentage and had a short-list of candidates. Interestingly, she was the one that looked the least likely on paper
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  #3  
Old 5th June 2018, 05:27 PM
Woody1 Woody1 is offline
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Unfortunately, mtDNA won't be of any use because the ancestor I'm searching for is my mother's paternal grandmother. That's why I'm hoping to use X-DNA.
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  #4  
Old 5th June 2018, 11:37 PM
Fern Fern is offline
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mtDNA I didn't mention mtDNA.

The matches I referred to in my earlier post were all autosomal matches. But they matched me on one (or more) of the chromosomes numbered 1-22, and not on the X chromosome.

From what I understand, finding meaningful X matches can be problematic.

Perhaps someone more knowledgeable than me can help.
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  #5  
Old 5th June 2018, 11:57 PM
prairielad prairielad is offline
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Quote:
Originally Posted by Woody1 View Post

...

So my mother will likely have inherited one x-chromosome passed from her maternal grandmother, while my uncle should not have any x-dna matches from that maternal grandmother. I want to find x-matches to my mother that are not in common with my uncle.

......
Unclear on above statement

Your mother, for her maternal X, will have a random mixture of her mothers maternal and paternal X's. Her maternal X will contain XDNA from both her maternal Grandmother and her maternal Grandfather.

The same applies for your Uncle (her brother)

Do you mean their paternal Grandmother?
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  #6  
Old 6th June 2018, 08:21 AM
Woody1 Woody1 is offline
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Quote:
Originally Posted by prairielad View Post
Unclear on above statement

Your mother, for her maternal X, will have a random mixture of her mothers maternal and paternal X's. Her maternal X will contain XDNA from both her maternal Grandmother and her maternal Grandfather.

The same applies for your Uncle (her brother)

Do you mean their paternal Grandmother?
Yes, absolutely right, I meant "paternal grandmother". My mother should have inherited an X-Chromosome intact from her paternal grandmother, while her brother should not have any x-matches to that paternal grandmother. I'd like to find people who match to my mother, but not to my uncle. Even better would be the ability to find out which chromosome people are matching to, but I don't know if that's possible.
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  #7  
Old 7th June 2018, 07:25 AM
Fern Fern is offline
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Quote:
Originally Posted by Woody1 View Post
Even better would be the ability to find out which chromosome people are matching to, but I don't know if that's possible.
Gedmatch Tier 1 includes a Matching Segment Search tool.
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  #8  
Old 7th June 2018, 07:52 AM
Woody1 Woody1 is offline
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Quote:
Originally Posted by Fern View Post
Gedmatch Tier 1 includes a Matching Segment Search tool.
Perfect! I'll check it out.
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  #9  
Old 9th June 2018, 09:21 AM
Woody1 Woody1 is offline
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Also, for anybody who might have a similar need, try DNA Painter. This site lets you add segment data, then creates a color chart which highlights your matches. Very clever!
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