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Archiver > GENEALOGY-DNA > 2010-11 > 1288622423


From: John S Walden <>
Subject: Re: [DNA] Help with analysis of Family Finder Results
Date: Mon, 1 Nov 2010 10:40:23 -0400
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I have figured out the splitting of blocks issue

FTDNA will "bridge" a block across the centemere but does not bridge it
across one
of the SNP poor regions.
I wonder if there is a "right" way to handle this.
If there are no SNPs there then the two people match 0 = 0 thus it should
bridge??

John W


On Thu, Oct 28, 2010 at 10:10 AM, John S Walden <>wrote:

> I went back to the raw data and did a bit of my own analysis on a slightly
> different set of people.
> I analyzed Darnell my 4th Cousin on my father's side, Hughes, an aunt on my
> mother's side
> an my own Family Finder data.
>
> I worked only on chromosome 16 because I had matches to each on 16
> NAME MATCHNAME CHROMOSOME START LOCATION END LOCATION CENTIMORGANS MATCHING
> SNPS John Shelby Walden Jean Walts Hughes 16 10435114 31286856 29.57
> 3496 John Shelby Walden Jean Walts Hughes 16 31292149 85385029 63.78
> 9679 John Shelby Walden Larry D. Darnell 16 60832845 88586837 44.66
> 6987
> I confirmed that indeed the start and end locations are not exact and in my
> case were off by up to 100 SNPs
> The "real" block is always a bit larger than what is reported. Ann Turner
> mentioned this in the last email on this thread.
>
> I also found that in the Walden/Hughes case the "real" match is only one
> and not two blocks
> SNP 31292149 is the next SNP after 31286856 so there is no break in the
> match.
>
> In my view this is a reporting error that should be fixed as it could
> affect the analysis
>
> Not so much in my case as the blocks are already large.
> But if each of the two blocks were to be say 6.5 cM that is a much
> different situation than one block at 13 cM
>
> I did send a note to info at FTDNA with my finding.
>
> By combining the Walden and the Darnell results I have created a 44 cM
> block on Chr 16 that is known to
> be from the marriage of Richard Walden and Phebe Kemper married in 1817 in
> Henry County KY
>
> I hope to be able to use this deduced result to confirm or eliminate that
> branch of my tree with matches
> to other "distant" cousins.
>
> Does that theory make sense?
>
> John W
>
>
>


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