Just got my uncles Y DNA Tests results back (a male Bryant descendant of John P Bryant and Virginia Cooper).

Matches 3 Irish Breen/O'Brien's. Interestingly they are from other countries too. One of them he matches at a genetic distance of 1 at 37 markers which suggest a shared ancestor around 8-12 generations back or so and their Breen came from Ireland in the mid 1800s. So it seems pretty solid our Bryant line is Irish (that article seems to be right on the family lore in that regard).

He matched only one American Bryant, only at a genetic distance of 3 which unfortunately could mean a match from 8-20 generations or so, pretty broad. I will have to upgrade my uncles test (and get the other Bryant to upgrade his test) to be able to narrow down how closely we relate.

You can see that Bryant's believed ancestry line here:
http://boards.ancestry.com/surnames.briand/37.3.1.1/mb.ashx

Unfortunately due to the match not being very close at 37 markers our shared Bryant ancestry could be even before coming to America, though it definitely is somewhere back there. It could also be much closer. On my personal Langley Y DNA results I match descendants of two brothers that share an ancestor about 8 generations ago, one matches a genetic distance of 0 and the other 3 despite being the same relation (at 37 markers too)...

What's interesting is that the match's Bryant line runs into Cherokee intermixed Bryants including some that resided in Northern Georgia. A Lucy Bryant mother of John Bryant born 1775 in his list was part cherokee, she is in the 1817 Cherokee rolls for getting a 640 acre reservation in Northern Georgia (around where Helen, Georgia is now) which is quite close to Madison County, Georgia where the last known place of John Bryant father of John P Bryant was (he also owned land in Hall County, Georgia which is even closer to that area).

It could be coincidence but definitely curious if there's a connection, especially considering I've heard that there's Cherokee ancestry up that line, one family story I recently heard is that Elias Bryant son of John P Bryant was 1/18 cherokee (an oddly specific number). There's also some rejected Eastern Cherokee applications claiming a father of a Nancy Bryant from madison county Georgia (born around 1790) who was called "Frosty" or "Neddie" Bryant was part cherokee. Nancy married Moses Peyton and John Bryant b 1785 (father of John P) not only is the only Bryant with the earliest roots in Madison County Georgia but he lived next to Peytons and they seemed to have some interaction (John and John P acting as chain carriers for surveying Cornelius Peytons land (a brother of the Moses married to Nancy Bryant). So it seems quite plausible Nancy Bryant was a sister of John... though pure speculation at this point. Either way there seems to be enough hints that the stories of Cherokee up the Bryant line might be correct and if so then this match might explain some of it.