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-   -   Match at 67 but not 111 (http://forums.familytreedna.com/showthread.php?t=41967)

Dawn Ellis 25th June 2017 01:59 PM

Match at 67 but not 111
 
Hi guys,

I have a member of my project that matches two other members at 67 markers (GD 7), but not at 111 markers. Does this just indicate that the match is so long ago that it is not genealogically relevant or are they not not related at all?

Thanks,
Dawn

MMaddi 25th June 2017 02:33 PM

Has their 67 marker match also tested to 111 markers? If not, then FTDNA can't compare your project members to this 67 marker match at the higher level. The match page will tell you how many markers each match has tested.

If the 67 marker match has tested 111 markers and isn't on your project members' match list, that indicates the match is not close. Already, with a GD of 7 at 67 markers, the match barely made the threshold to be declared a match. I regard a 60/67 match as probably representing a common ancestor several hundreds years ago, barely in a genealogical time frame. So, it would not be surprising if the match falls away at the higher level.

Dawn Ellis 25th June 2017 04:42 PM

One of the two matches did test 111. The other only 67.

mattn 25th June 2017 05:18 PM

Quote:

Originally Posted by Dawn Ellis (Post 441134)
One of the two matches did test 111. The other only 67.

it doesn't sound like they are actually related unless they have an unusual amount of mutations. Do these men share the same surname?

Dawn Ellis 25th June 2017 06:27 PM

No, different surname.

villandra 19th July 2017 03:45 PM

If they match at 67 markers, then it's highly unlikely that they match by accident.

The 111 marker test is sometimes (not always) helpful when you're trying to pin down when the most recent common ancestor lived, or else find the nonsurname match closest to a given person's Y DNA. In the latter case I've seen it yield mostly confusion and little help.

I've found the test most useful when trying to determine if people match within a 300 to 500 year time frame.

Failing to match at 111 markers does NOT mean it isn't a match. I've seen people with the same surname and solid paper trails match at 67 markers and not at 111 markers. This test is superfluously restrictive for most peoples' purposes.

I'm finding it somewhat useful when trying to determine which matches among a medieval group of families, match in the past four or five hundred years. There are holes in teh ability of the existing marker choices to determine TMRCA at that distance, as the fastest changing markers dance in circles at that point and noone seems to konw what to make of them. And predictably only a couple of people have the will and the means to do the Big Y - and then there's learning to extract and identify the relevant SNPs.

RVBlake 20th July 2017 11:51 AM

67-MARKER
 
I have a 67-marker Y match, with a genetic distance of 1, with a fellow of different surname. In your opinion, roughly when do we share a TMRCA?

Armando 20th July 2017 07:26 PM

67 markers (GD 7) is very distant and not normally from a common ancestor in the past 500 years. The common ancestor can be from more than 1,500 years ago. John Cleary has an excellent video that presents this with both Y67 test results and BigY test results. The video is at https://youtu.be/pxexkvfus6w

A 67-marker Y match, with a genetic distance of 1, is very close and the matching would likely still be close at Y111 and with BigY testing but further testing is needed to determine the relatedness of the match.

A former haplogroup admin has a thread on Anthrogenica about his surname Y111 matches also getting BigY testing to determine the relationships between them.

TwiddlingThumbs 21st July 2017 05:35 PM

Quote:

Originally Posted by Dawn Ellis (Post 441138)
No, different surname.

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.

TwiddlingThumbs 21st July 2017 08:45 PM

Quote:

Originally Posted by TwiddlingThumbs (Post 442054)
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.

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


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