We do now have some yDNA, and more autosomal DNA (atDNA), evidence bearing upon our O’Brien/O’Bryant quest.
According to Find A Grave 84421922, our Alfred was a brother of Wilford, Joseph, Peter III O’Brien, & others. Several autosomal DNA kits from descendants of brothers Alfred, Wilford, Peter III are mutually inter-matching & sizable. A descendant of Wilford has tested 37 STR (Short Tandem Repeats) markers on yDNA. Several men in his match group have tested SNP (Single Nucleotide Polymorphism) markers. Our O’Brien/O’Bryant Haplogroup R1b phylogenetic tree SNP sequence includes these markers: L21+ (Atlantic Celt) -> L226+ (Irish Type III, Dalcassian) -> DC782+ (County Clare divergence from Brien Kings of Munster, c. 1100 AD?) -> DC297+ (Terminal SNP specific so far to part of our O’Brien group of interest in the O’Brien yDNA Project). Other matching men did not test SNPs down this far, so those kits were placed in another grouping in the O’Brien yDNA Project at https://www.familytreedna.com/public/obrien?iframe=ycolorized
In this project, find these two groups of matches of Wilford:
(1) Terminal SNP DC297+: The O’Bryan families who migrated to the Carolinas. 33 & 34 of 37 STR matches with Wilford’s descendant. Kit # B122229 is from a descendant of Thomas O’Bryan (1760-1827) of Chatham County NC. The yDNA Most Recent Common Ancestor for our O’Brien of Va -> Ky -> Ross/Pike Ohio Chatham NC lines may have been prior to 1725, in Ireland.
(2) Group containing Kit # 34330: From Daniel O’Brien b. 1823 County Limerick, a 33 of 37 STR markers match with Wilford’s descendant, & close to the Mode STR values for that inter-related group. STR Modes yield the best estimate of the profile of a man ancestral to all in that group. In this group is Kit # 83123 for James Brient b. 1788 Knockanore Waterford. This man was ancestor of owner of atDNA Kit M225148 who has a sizable atDNA match with A467138, descendant of Alfred. So, James Brient is shown to have been kin by yDNA to Wilford & kin by atDNA to Wilford’s brother Alfred. A double & solid Waterford connection to the Ross/Pike Ohio line.
At www.gedmatch.com Kit A238437 is a descendant of Alfred (b. 1807, Ohio). Kit M225148 is a descendant of James Brient (b. 1788, Waterford). The shared segment for these kits is 25.6 centiMorgans on Chromosome 13. There are several other kits which triangulate at this location. Triangulations (sticky segments resisting recombination) can mean that the MRCA for everyone in the group was more generationally remote than one might otherwise expect for a shared segment of this size. Maybe a MRCA who lived well before 1700 in Ireland. On another chromosome, the James Brient (b. 1788) descendant has a shared segment with a descendant of William O’Brien (b. 1695, Londonderry). However, William (R1b-M222+ = Lowland Scot & Northwest Irish) was not a yDNA match with our Wilford (= R1b-L226+, Irish Type III, Dalcassian). Our R1b L226+ O’Brien is not French, & not from Cornelius b. 1697 of County Clare (= Irish Type II, R1b-CTS4466 -> A7753). https://www.familytreedna.com/public/obrien?iframe=ycolorized
The Wilford O’Brien descendant’s yDNA has a 34 of 37 STR markers match with a reported descendant of Charles O’Brien/Bryant (b. 1725). This kit tested to SNP = R1b-Y5610+. At https://www.yfull.com/arch-6.05/tree/R1b/ this marker is said to have mutated 1100 years ago, thus possibly shortly before the time of King Brian Boru (941-1013), who was kin to our group, but likely not its ancestor. Boru has his own Terminal SNP in the O’Brien yDNA Project. The trail to Y5610+: R1b-L21+ (Atlantic Celt) -> L226+ (Irish Type III, Dalcassian) -> Y4010+ -> Y5609 -> Y5610+. Downstream from this would have been the peel-off of the County Clare group from the line of Brien Kings of Munster, & still later the peel-off from the Clare Group to markers increasingly focal to our O’Brien close kin.
John Charles O’Brien/Bryant (b. 1725) appears to have been the yDNA/atDNA Most Recent Common Ancestor for descendants of Enoch (b. 1760) versus descendants of his brother Peter Sr. (b. 1750) -> Peter Jr. (b. 1772) -> Alfred, Wilford, Peter III, Joseph etc. atDNA cross-matches between descendants of Alfred & Peter III are sizable, suggesting that they were not more distant than brothers, as reported. Several descendants of Peter III have nearly 28 centiMorgans of shared segment triangulated on Chromosome 20 with Kirk T945852 (descendant of Alfred). A descendant of Peter III has on Chromosome 9 a 16.4 cM shared segment with atDNA kit FR3254794 named at this site: https://www.wikitree.com/wiki/O'Brien-2028 a descendant of Wilford. This Wiki Tree page manager also has a tree at Ancestry.com https://www.ancestry.com/family-tree/tree/76148335?cfpid=40339724659&dtid=100
where one can see that Daniel Mack O’Brien & his wife Mary Jane Hopper both had the same O’Brien ancestry: The father (& unknown mother) of Peter O’Brien Sr. & his brother Enoch O’Brien, respectively.
