19/09/2025
Just completed the first DNA review (using Y-DNA & atDNA) of my wife's paternal lineage, the O'NEILLs, here in West Cork.
Thanks to many people willing to share their DNA results, it was possible to show that the O'NEILL families and branches, as accounted for in the old letter provided by a family member, rings true genetically. Until the letter, we had nothing to go on before the early 1800's, as is typical with Irish church records. The result is a pleasant surprise and again, a good indicator what can be possible with DNA.
In terms of atDNA we now know the descendant Reenroe townland families of my wife are related to those at and at ; all townlands north of .
The letter describes that Sean O'NEILL arrived with a priest from "after the Siege" (so late 1690's or early 1700's) and settled in then , with one branch remaining at Ballinard and other branches settling in , Knocks & Derrymilleen. The only non-proven DNA line is the one still at Ballinard, as there were no testers.
The Y-DNA was surprisingly helpful since is showed that this particular O'NEILL clan is from the sept , which can trace their male lineage historically back to the 5th & 6th centuries in Munster.
What no-one expected was the Y-DNA showing that the male line at Derrymilleen was related to the O'NEILLs who settled townland (next to Reenroe) from . Being only one mutation removed, it strongly suggests that one of the told 'five sons of Sean' (or a grandson) must have gone to Drimoleague, before descendants settled alongside their Reenroe cousins at Cashelisky.
Findings are reported in my column in .