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  #11  
Old 22nd July 2017, 09:35 AM
Armando Armando is offline
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Quote:
Originally Posted by TwiddlingThumbs View Post
If it's a different surname, then a gd at 67 does not mean they match. Lots of false positives with different surnames. FTDNA's gd guidelines re matches only apply to men with the same surname.
There are too many NPEs to be able to state that a 67 marker match with a person that has a different surname isn't a match from a genealogical timeframe. The false positives can only be confidently be weeded out by Y111 and/or BigY testing or a similar NGS or WGS test.
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  #12  
Old 22nd July 2017, 09:44 AM
Armando Armando is offline
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Quote:
Originally Posted by TwiddlingThumbs View Post
Per the following ISOGG article on convergence, a low gd number with someone of a different surname may not indicate any relationship. The lower gd may due to convergence, ie, two unrelated lines having STR results that converged due to a series of mutations that closed the STR marker gap between the two lines. The likelihood that a low gd may be due to convergence depends on a lot on your haplotype. According to the article, for 5-10% of surname groups, up to 90% of their matches might be false positives. If you have a close gd with someone of a different surname, it is worth a look, but may not indicate any relationship. https://isogg.org/wiki/Convergence
This is from your convergence link "It is less likely to occur at 67 markers, though a case has been reported of two 67-marker haplotypes with a genetic distance of 6, which were found to be in different R1b subclades"

What they don't say in that sentence, but should, is that a match with a GD of 6 or 7 has a very high probability of not having a common ancestor in the past 500 years which generally most people can't even get past that in their genealogy. They also fail to mention that some 67 marker matches no longer match once the person and the match upgrade to Y111 and that this is due to not having a common ancestor in the past 500 years. Beyond 500-1,000 years then STRs are less reliable than NGS testing estimate how long ago the common ancestor lived.

Last edited by Armando; 22nd July 2017 at 10:22 AM.
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  #13  
Old 22nd July 2017, 05:40 PM
clintonslayton76 clintonslayton76 is offline
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In other words....

In simplest terms, if two 67 matches, regardless of surname, each expand their results to 111, they should not diverge from matching if they share a common ancestor within historical genealogical terms. If they continue to show as matches, then it should be investigated as possibly findable with paper genealogy. The genetic distances are guesses, but having 67 matches with the same surname should not mismatch at 111, the mutations are "more recent" but the haplo is not affected. With different surnames, a close match bears further research, but enough mutations to show 6 to 7 gens is probably not worth your time unless there is supplementary evidence to create suspicions.
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  #14  
Old 16th September 2017, 10:24 AM
Dawn Ellis Dawn Ellis is offline
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Comparing the snps

So with this group, two of the men have done snp testing. One is R-BY11542, the other is R-S1688. The men have different surnames. I am looking at both of their snp pages. As far as I can tell S1688 is upline from By11542, but it is really hard to follow on the chart, having to scroll. Is there a resource for comparing snps making it easier?
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  #15  
Old 20th September 2017, 07:19 PM
clintonslayton76 clintonslayton76 is offline
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I have never seen one

The trees for SNPs along the Y line do not match across services: ISOGG, FTDNA, Yfull have trees, but all such trees are somewhat experimental. I have never received or seen any explanation on FTDNA that breaks down YBP or why my own terminal SNP has been "refined" twice.
Occasionally I have Googled a SNP term and found something, but never for my most recent terminal at FTDNA. YFull gives an entirely different SNP name, but at least shows YBP as interpreted by YFull.
The answer to your question as far as FTDNA is: you have to contact a haplo admin and be at their mercy, because obviously some of the terminology is proprietary. The SNP tools at FTDNA are not really there except as (as you say) a difficult tree that says "you are here because we say so."
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  #16  
Old 20th September 2017, 10:24 PM
Armando Armando is offline
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Quote:
Originally Posted by Dawn Ellis View Post
So with this group, two of the men have done snp testing. One is R-BY11542, the other is R-S1688. The men have different surnames. I am looking at both of their snp pages. As far as I can tell S1688 is upline from By11542, but it is really hard to follow on the chart, having to scroll. Is there a resource for comparing snps making it easier?
It's also important to find out which SNPs the S1688 person tested negative for. If he only had an SNP pack or an individual SNP test and wasn't tested for SNPs downstream or at least not for the SNPs that lead to By11542 then there is no way to tell if the S1688 person really is positive for BY11542.

S1688 is without a doubt upstream from BY11542. The BY SNPs have been named by FTDNA. BY likely stands for BigY. So it was discovered by FTDNA through BigY testing and won't always show up in other trees. What you can do sometimes is find phylogenetic equivalents, or SNPs directly upstream, and look them up at https://www.yfull.com/search-snp-in-tree/

BY11542 isn't in the YFull tree but U198, which is directly upstream, is at YFull at https://www.yfull.com/tree/R-U198/ so that is as good as you will get for that SNP at YFull for now.

So since BY11542 and S1688 are U106 SNPs it is best to get with the admins of the U106 projects.
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  #17  
Old 21st September 2017, 02:17 PM
MMaddi MMaddi is offline
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Quote:
Originally Posted by Armando View Post
So since BY11542 and S1688 are U106 SNPs it is best to get with the admins of the U106 projects.
While it is true that U198 is a subclade of U106, the R1b-U106 Project doesn't accept those who are U198+. This is due to an agreement with the administrators of the U198 and L1 (another U106 subclade) projects. Since they already had been set up before the R1b-U106 Project and have seniority, they have sole project administrator access to those who are U198+ or L1+. There is some collaboration between the R1b-U106 Project and L1 Project in analyzing Big Y results.

Dawn Ellis should join her relative's results to the U198 Project at https://www.familytreedna.com/public/U198/.
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