We are delighted to announce that Francis Mac Dermot, current The Mac Dermot and Prince of Coolavin, has graciously undergone Y-DNA testing at YSEQ GmbH. He is now known to be in the R1b-BY20594 clade, which is a subclade of the R1b-BY20602 clade, which in turn is a subclade of the R1b-FGC5939 clade. Further refinement testing is still underway.
Current evidence strongly indicates that the R1b-FGC5939 clade is completely, or at least one branch of, the Uí Briúin Aí, Maicne Eócháda Tírmchárnai, while its R1b-BY20602 subclade is providing strong evidence of being the Síl Muiredaig. This now confirms the three major branches of the Uí Briúin are under the R1b-A260 clade, which corroborates the genealogy of the three sons of Fergus being the progenitors of the three traditional branches of the Uí Briúin.
It does, however, bring into question as to whom the later O’Conor lines descend from, since they are in the R1b-Y166841 clade that is parallel to the R1b-A260 clade. We previously had the gracious participation of a well documented O’Conor Don scion to prove the R1b-Y166841 clade descent.
The one recorded explanation found to date for this divergence from the traditional genealogies is given in Peter O’Connell’s King List of Connacht that was published in James Hardiman’s 1846 edition of Ruaidrí Ó Flaithbertaig’s A Chorographical Description Of West Or H-Iar Connaught. In that list, Peter O’Connell shows a genealogy not seen in most other recorded genealogies, and that is that Muiredach Máel, son of Eógan Sríab, son of Dau Galach, son of Brión, the eponymous progenitor of the Uí Briúin, had TWO sons: Fergus and Cathal.
This fits with the fork we see between the R1b-A260 clade, the Maicne Fergusa, and the parallel R1b-Y166841 clade, the likely Maicne Cathail. Some of Peter O’Connell’s works can be found at the Royal Irish Academy Library.
So it would appear that sometime after Tadc inda Dúir Ó Conchobair, d. 956 AD, but before or with Tairdelbach Már Ó Conchobair, d. 1156 AD, there was an SCE (Surname Change Event) in the Ó Conchobair line that introduced the likely Maicne Cathail line into the later Ó Conchobair lines. We deduce this since Tadc inda Dúir Ó Conchobair was the last common ancestor of the Mac Diarmata and the Ó Conchobair.
We are also confident about this deduction because we are seeing other Conner and variant surnames in the R1b-FGC5939 clade, which tends to indicate that other branches of the Ó Conchobair, separate from the Tairdelbach Már Ó Conchobair line, did leave descendants in the Síl Muiredaig line. As far as we know with the current data, it is only the descendants of Tairdelbach Már Ó Conchobair, that are being found in the R1b-Y166841 clade. However, we are NOT saying the SCE occurred with Tairdelbach Már Ó Conchobair, but that he was of the likely Maicne Cathail line is evident by his descendants.
This leaves the Mac Diarmata as being the senior line of the Síl Muiredaig, genetically speaking. While this is an egregious discrepancy with the standard genealogies on the one hand, on the other hand it is confirming these genealogies by showing the appropriate genetic connection between the three traditional branches of the Uí Briúin, all descending from a common progenitor under the R1b-A260 clade. So if you will, this is the exception that proves the rule. This is a very exciting corroboration of part of Ireland’s history that in this latter age has been too often scoffed at.
