37 marker upgrade complete..what to make of the results

[vharris]

Recently, myself and another researcher each submitted DNA Y-12 tests. My ancestor born was William B. Green born about 1803 in South Carolina. This other researcher was descended from Lewis Green born 1801 in South Carolina. Both of our ancestors are living in the same county in 1830. I believe them both to be the son of the same man, a preacher named Thomas Green who was born about 1777 in South Carolina.

We both ordered our DNA kits at the same time with the hopes of proving that our ancestors were brothers.

The 12 marker results, we matched perfectly. We both upgraded our kits to 37 markers last month and the results just came back. We both match 36 out of 37 markers. The marker were we differ is DYS570, I have the value of 20 here while the other researcher has the value of 19.

While I was waiting on the upgrade, I continued my traditional research. I think I have proven that there were two different Green families in this same county. However, it is looking as though the two different families were related.

Besides Reverend Thomas Green, a Richard Green had moved to the county about 10 to 15 years earlier and appears to be the ancestor to these other Greens. But to complicate matters more, evidence seems to suggest that the two families are related. It appears that Richard is an uncle of Reverend Thomas Green, Richard being the brother of Reverend Thomas Green's father.

So from these results, can we make any assumptions about our two ancestors being brothers or cousins? Or will more markers be required?

Also, between me and my cousin, we match two other families with different surnames 36 out of 37 markers. Does this mean we are closely related to these other families or again, is more markers required?

Any help would be appreciated.

[gtc]

Given the same surname and that small difference, I'd say that you're related.

FTDNA says:

"A 36/37 match between two men who share a common surname (or variant) indicates a close genealogical match. Very few people achieve this close level of a match, and it is within the range of most well-established surname lineages in Western Europe.

It's most likely that they matched 24/25 or 25/25 on a previous Y-DNA test, and the mismatch will be found within DYS576, DYS570, or CDY."

[MMaddi]

Based on what you've posted about Thomas Green and Richard Green and the 36/37 match between you and the other researcher, I think it's likely that Thomas and Richard were related. However, I don't think you can infer whether Thomas and Richard were brothers, cousins or uncle/nephew.

A close or exact DNA match at 37 or more markers with the same surname tells you with high probability that two men have a common paternal line ancestor within a genealogical time frame. gtc quotes the FTDNA FAQ addressing this. However, given the random nature of mutations, the match can't tell you exactly who the common ancestor is or how many generations back he is.

You could both upgrade to 67 markers, but according to the FAQ at http://www.familytreedna.com/faq/answers.aspx?id=9#923 "A 65/67 or 66/67 match between two men who share the same surname (or a variant) indicates a close relationship." If the match were 63/67 or 64/67, "The common ancestor is probably not extremely recent, but is likely within the range of most well-established surname lineages in Western Europe." The 38-67 markers are fairly stable, so you might get no or one differences among those markers if you both upgrade. Another possibility is to find some known descendants of Richard Green to test and compare to you and the other researcher.

You should concentrate on researching the paper trails of Thomas and Richard Green. That's the only place where you can possibly find a definitive answer.

[vharris]

Understood, thank for the replies.

What should I make of the 36 out of 37 marker matches to people with a different surname? Or the 35 out of 37 matches to a different surname. I have been able to find very little online about that.

[tomcat]

...What should I make of the 36 out of 37 marker matches to people with a different surname? Or the 35 out of 37 matches to a different surname. I have been able to find very little online about that.

Is the sole difference with these other-named folks also 20 vs 19 on DYS570?

What about the 35:37 matches?

[vharris]

Is the sole difference with these other-named folks also 20 vs 19 on DYS570?

What about the 35:37 matches?

I can tell that, as far as I know. I have been having problems with Ysearch for awhile, I get error messages.

In family tree's website, I can't see the other people's information, just how many steps removed from me they are. Unless there is some other way to tell this information?

[tomcat]

I can tell that, as far as I know. I have been having problems with Ysearch for awhile, I get error messages.

In family tree's website, I can't see the other people's information, just how many steps removed from me they are. Unless there is some other way to tell this information?

They may be participants in an I1a project that you might join. Or you might post an inquiry to an I1a project admin to get her or his take on the matter. I believe both FTDNA and Ysearch offer personal contact options - you may be able to interest those others in the mystery - your mystery and theirs. In addition, you and you cousin might test your I1a to the maximum so as to present to those others an elaborated target/challenge.