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Top of the mornin’

Happy St. Patrick’s Day to all the Irish, the Irish-Americans and the Irish-wannabes!

So… are you Irish? Really Irish? Irish right down to your molecular level? Irish in your very DNA?

The answer is… well… maybe.

And you may even be able to prove it.

Now that doesn’t include The Legal Genealogist who once heard a Buchanan cousin announce at a family reunion that we were all descended from the Great Irish Kings of some ancient century, third or fourth as I recall, and whose proof consisted of something vaguely along the lines of “well, we’re Buchanans and I read it on the Internet.”1 The fact that our paper trail dead-ends with James Buchanan who died in Maryland in 17512 is just a detail.

No, you need to be male, because the DNA that’s associated with a distinctive Irish type is a set of YDNA markers generally known as those of Niall Nóigiallach – Niall of the Nine Hostages.

And YDNA, remember, is the kind of DNA that only men have and that passes from a father only to his sons and from his sons to his grandsons and so on.3

In 2006, researchers from Trinity College in Dublin announced that a high percentage of Irish men, including roughly one in five in northwestern Ireland, all had the same basic set of YDNA markers. The study they’d conducted showed “a significant association with surnamed purported to have descended from the import important and enduring dynasty of early medieval Ireland, the Uí Níill.”4 They found that roughly 8% of Irish men had that YDNA chromosome, 21% in northwestern Ireland — and as much as one in 50 of American men who are descended from Irish immigrants with names like O’Connor, Flynn, Egan, Hynes, O’Reilly and Quinn.5

Formerly called R1b1c7 and now known as R-M222, that haplogroup has these markers:

Niall of the Nine Hostages markers

(Image from Family Tree DNA)

And that YDNA signature, it’s believed, suggests that “the 5th-century warlord known as ‘Niall of the Nine Hostages’ may be the ancestor of one in 12 Irishmen.”6 True, the study authors didn’t go quite that far. They concluded: “Figures such as Niall of the Nine Hostages reside at the cusp of mythology and history, but our results do seem to confirm the existence of a single early-medieval progenitor to the most powerful and enduring Irish dynasty.”7

So who was this Niall dude anyhow? Well… that’s a bit tough to report reliably, since nobody was around in the fourth century writing down history and preserving it. Assuming he’s on the history side and not the mythology side, he’s supposed to have reigned between 368 A.D. (or maybe 378 A.D.) and 395 A.D. (or maybe 405 A.D.)… and maybe later.8

There’s a wonderful purely legendary biography of Niall that has him left on the ground to be eaten by birds but rescued by a poet and hidden away until he’s grown and kissing a hag who turns into a princess and grants him and 26 generations of descendants the High Kingship of Ireland.9 (Hey, I said it was legend.)

In any case, Niall is supposed to have had sons. Lots of sons. And grandsons. And great grandsons. And that’s perfectly consistent with the Ireland of that time and for some time thereafter. The study authors note that “even though medieval Ireland was Christian, earlier marriage customs persisted and allowed divorce and concubinage” and they cited as an example an Irish noble in the 15th century — purportedly a Niall descendant — who himself “had 18 sons with 10 different women and counted 59 grandsons in the male line.”10

So if your YDNA is R-M222, a particularly happy St. Patrick’s Day to you!

We’ll leave the issue of all those Scots with R-M22211 for another day…


  1. See, e.g. “Origins of Clan Buchanan,” Our Buchanan Family ( : accessed 16 Mar 2013) (“Another commonly accepted account relates that Anselan Buey O’Kyan also known as Auslan O’Cahan (pronounced O’Kane), descended from the long line of Irish Kings, was son to the King of Ulster”).
  2. Probate file, Estate of James Buchanan, Charles County MD, 1751-1752; Prerogative Court, Accounts, Liber 33, folio 141.
  3. ISOGG Wiki (, “Y chromosome DNA tests,” rev. 21 Jan 2013.
  4. Laoise T. Moore, et al., “A Y-Chromosome Signature of Hegemony in Gaelic Ireland,” American Journal of Human Genetics 78 (Feb 2006): 334-338.
  5. Ibid. See also Nicholas Wade, “If Irish Claim Nobility, Science May Approve,” New York Times, online edition, published 18 Jan 2006 ( : accessed 16 Mar 2006).
  6. Matching Niall Nóigiallach – Niall of the Nine Hostages,” Family Tree DNA ( : accessed 16 Mar 2013).
  7. Moore, et al., “A Y-Chromosome Signature of Hegemony in Gaelic Ireland,” American Journal of Human Genetics 78: 338.
  8. Wikipedia (, “Niall of the Nine Hostages,” rev. 16 Mar 2013.
  9. Ibid.
  10. Moore, et al., “A Y-Chromosome Signature of Hegemony in Gaelic Ireland,” American Journal of Human Genetics 78: 336.
  11. See “R-M222 Haplogroup Project (formerly the R1b1c7 Project)- Background,” Family Tree DNA ( : accessed 16 Mar 2013).
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