son of) Y, or X ua (
grandson or descendant of) Y, which became simplified to Ó. For example O’Brien meant grandson/descendent of Brian. Surnames in the form O’Brien could easily be passed down to the next generation, becoming inherited surnames. In time the Mac forms were also handed down. The Anglo-Norman conquest of Ireland from 1170 onwards brought in new surnames. It also led eventually to the decline of spoken Gaelic. Many Irish surnames were haphazardly and inconsistently converted to English language forms. In some counties this was enforced.1E. MacLysaght,Irish Families: their names, arms and origins(1985). However the exceptional age of Irish surnames open up exciting possibilities for tracing links with haplogroups.
Early attempts at linking haplogroup and Irish surname were perhaps over-hasty in their conclusions. The Y-DNA haplogroup R1b-M222 was initially thought to mark the descendants of Niall of the Nine Hostages. It is carried by nearly 20% of the men in Donegal today. In early historic times this was the territory of the northern Uí Néill, presumed descendants of the fabled 5th-century warlord. R1b-M222 is particularly common among those with some Uí Néill surnames, such as O'Doherty, though not most of the O'Neills themselves. It also appears among the Connachta, supposed descendants of the brothers of Niall.2L.T. Moore, B. McEvoy et al., A Y-Chromosome Signature of Hegemony in Gaelic Ireland, The American Journal of Human Genetics, vol. 78, no. 2 (1 February 2006), pp. 334-338. However its concentration among Lowland Scots (rather than in Gaelic Argyll) and northern English suggests that it is centuries older than Niall.3N.M Myres et al., A major Y-chromosome haplogroup R1b Holocene era founder effect in Central and Western Europe, European Journal of HumanGenetics, (advance online publication 25 August 2010); http://www.familytreedna.com/public/R1b1c7/; J.D. McLaughlin, Ui Neill DNA http://clanmaclochlainn.com/dna.htm.So it is more likely to be a La Tènemarker, present among the people of north-western Ireland long before the Uí Néill established their dominance there, unrelated to the Uí Néill elite.
Yet there are interesting links emerging between subclades of R1b-L21 and Irish surnames related to two kindreds of Munster marked on the map of Ireland c. 800 AD: the Dál Cais and Déisi Mumhan. The marker L226 defines what used to be known as the Irish Type III haplotype, linked to a group of Dalcassian surnames: O'Brien/Bryant, O'Casey, McCraw/McGraw/McGrath and O'Hogan. The Dál Cais or Dál gCais arose from obscurity among the peoples of Munster in the 7th and 8th centuries AD, when they pressed north into Thomond (now County Clare), expanding the territory of Munster. They claimed descent from Cas, 6th in descent of Cormac Cas, supposed King of Munster in the 3rd century AD. Whether or not the early parts of this pedigree are reliable, the O'Briens take their name from Brian Boru, High King of Ireland 926-1014, and the family were kings, princes and earls of Thomond until the 18th century.4D.M. Wright, A Set of Distinctive Marker Values Defines a Y-STR Signature for Gaelic Dalcassian Families, Journal of Genetic Genealogy, vol. 5, no. 1 (Spring 2009), pp. 1-7.
Another marker - L144 - has been found among men with surnames such as Whalen and Phelan, derived from the personal name Faeláin. Faeláin (wolf) occurs a number of times among
the Irish royal houses. In fact two kings of that name died in the same year. The Annals of Ulster record the
demise in 966 of Faelán son of Cormac, king of the Déisi of Mumu [Mumhan], and Faelán, king of Laigin. The descendants of the former appear in the same annals as Ua Faeláin by
1085,5The Annals of Ulster: Corpus of Electronic Texts Edition. a step towards surname development. So we can expect at
least some Whalens and Phelans to descend from Faelán, King of the Déisi Mumhan, particularly those with origins in or near his former territory. The Déisi Mumhan then occupied
what are now the Counties Waterford and Tipperary. A number of the Whalens and Phelans carrying L144 can trace their origins to Laois, Kilkenny or Waterford.6http://www.familytreedna.com/public/whalen/Déisi
simply means vassal peoples. But by the 8th century déisi communities in the south-east had formed the sub-kingdom of Déisi Mumhan (déisi of Munster). Naturally their elite
promulgated the notion of the Déisi as an ancient tribe. In reality several unrelated kin-groups could have been united under that name. However the genetic marker L144 has also
been found in men of the Welsh surname Prosser.7Michael Whalen personal communication. The surname Prosser clustered in South-East Wales by the 19th
century: D. Hey,Family Names and Family History (2000), pp. 93-4.This may support the claim made in the Expulsion of the Déisi that one
of the royal Déisi line
Eochaid son of Artchorp went over the sea with his descendants to the territory of Demed. Philip Rance argues that they were recruited by the Late
Roman authorities to protect Demetia (south-west Wales) from Irish raids. 8P. Rance, Attacotti, Déisi and Magnus Maximus: The Case for Irish Federates in Late Roman Britain,Britannia, vol. 32 (2001), pp. 243-270.
Artchorp (Airtt Chirp) appears as an ancestor of Faeláin in an early pedigree.9Bodleian Library MS Rawlinson B 502, Corpus of Electronic Texts Edition,
section 19, item 1365: http://www.ucc.ie/celt/online/G105003.html or M.A. O’Brien, Corpus Genealogiarum Hiberniae, (Dublin, 1962), p. 253.
For information on many Irish surnames, see Ireland's History in Maps by Dennis Walsh.
- E. MacLysaght, Irish Families: their names, arms and origins (1985).
- L.T. Moore, B.McEvoy et al., A Y-Chromosome Signature of Hegemony in Gaelic Ireland, The American Journal of Human Genetics, vol. 78, no. 2 (1 February 2006), pp. 334-338.
- N.M Myres et al., A major Y-chromosome haplogroup R1bHolocene era founder effect in Central and Western Europe, European Journal of Human Genetics, (advance online publication 25 August 2010); http://www.familytreedna.com/public/R1b1c7/; J.D.McLaughlin, Ui Neill DNA http://clanmaclochlainn.com/dna.htm.
- D.M. Wright, A Set of Distinctive Marker Values Defines a Y-STR Signature for Gaelic Dalcassian Families, Journal of Genetic Genealogy, vol. 5, no. 1 (Spring 2009), pp. 1-7.
- The Annals of Ulster: Corpus of Electronic Texts Edition:http://www.ucc.ie/celt/published/T100001A/
- Michael Whalen personal communication. The surname Prosser clustered in South-East Wales by the 19th century: D. Hey, Family Names and Family History (2000), pp. 93-4.
- P. Rance, Attacotti, Déisi and Magnus Maximus: The Case for Irish Federates in Late Roman Britain, Britannia, vol. 32 (2001), pp. 243-270; Michael Whalen personal communication.
- Genealogies from Rawlinson B 502,1365, Corpus of Electronic Texts Edition: http://www.ucc.ie/celt/online/G105003.html.