Y-DNA Test Turned up a Perfect Match with Different Last Name

[larkspur3]

I'd love some advice from any of you who are more adept at the intricacies of DNA testing than my family is!

We had my brother's Y-DNA run on Family Tree DNA since he is a direct male descendant of our line, and he turned out to be a perfect match with someone who had a different last name. This has to be a NPE on the part of this other person, but we can't figure out how. While his last name, Terry, appears in the land records and church records of the very small local area where our ancestors lived, the name doesn't appear on our family tree, so there is no obvious place where someone might have had a child and handed it over to a brother-in-law or something like that. How do we go about eliminating possibilities to figure out how many generations back this event might have happened? Then we would at least know which group of men to start investigating.

[rlw254]

A perfect match at what STR depth (i.e. Y-12, 37, 67)? If it is 67+ then I would suggest analyzing the person's autosomal matches for those with your surname and see if you can find clusters descending from the same ancestor.

If it is below Y-67 you could be looking at an event many many generations back. I have a perfect Y-67 match with no common paternal ancestor for a minimum of 8 generations; anything smaller than this could be very difficult to find.

[Liz_in_Sussex]

Hi,

This might not be what you want to hear (sorry) - might it be your brother’s tree with the npe?

I manage a DNA project and we had a similar situation - but it turned out to be the person who was convinced theirs was the ‘true’ line that was actually not. Unless of course your brother matches others of his surname.

I agree with rlw254’s comments as the way forward though.

Liz

[Craclyn]

I agree with rlw254. Would you like to tell us which level of test he took? Has he joined the relevant surname group where the admins may be be able to advise you?

[Twdyr]

I have a similar problem to Larkspur. My surname can be traced through parish records in Cheshire and North Wales to the 1670's, but Y FTDNA only gives me 'same surname' matches at 12 marker level of testing. Most of the few matches at 67 & 111 level are with surname 'Hughes' in America.

I suspect a non-paternity event, perhaps familial emigration before 1670 or even Welsh patronymic name change.

Any ideas where I can go with this? Suggestions gratefully received with thanks.

[Craclyn]

Before jumping to conclusions about misattributed parentage consider the possibility that there may be nobody from that particular line who has tested Y-DNA with FTDNA. The test I admin has no matches at Y-111 and only has a couple of matches with GD 6 at Y-67. However, autosomal results confirm paternal ancestry back to the late 1700s. If you want more information on how your branch originated take a Big Y-700 test which will show you your branch on the haplotree.

[Twdyr]

Many thanks for the advice, Y-700 looks the way forward.

[rsel]

As others have said knowing which level test has been taken is critical to knowing, when two people may be connected, and if the test was on FTDNA, the Genetic Distance (GD) will then give you an approximate idea on the time line.   At a lower level test a GD of 0, whilst you might think is an exact match it could still be 1000's of years ago before Surnames came to be common.

If the test is one on FTDNA, join one of the discovery projects, as the people there are real experts and will be able to give you more solid timelines.

Richard

[Twdyr]

Thanks Richard,

My two principal matches have a genetic distance of
5 & 8 at 111 markers
4 & 7 at 67 markers
with TIP common ancestor between 12 and 20 generations ago.

I have belonged to a 'one name' study group for a year with nothing obvious showing,

Many thanks for your help
Philip