Maybe, but there are some things that have been omitted like Scottish/Northern English settlement in Ulster via the Plantations, which can account for some I-M223 in Northern Ireland. Obviously some I2 lineages in Ireland are representative of indigenous lineages.
County Down, where I-M223 was most concentrated, was not part of the official plantation.
Blood of the Celts theorizes that the Cruithne came into Ireland before the use of surnames, based on their later adoption of "Irish" surnames. It has the Cruithne (or Ui Echach Cobha) dating back to the 6th Century. Thus, the son (Mac) of Aonghusa (Angus) became McGuinness, the descendants of which became the lords of the Barony of Iveagh in County Down (known to carry I-M223).
"Haplogroup I2a2a1a1 (M284) is very rare outside the British Isles, except among those of British and Irish origin....The bearers of I2a2a1a1 (M284) have a mixed bag of surnames including English, Welsh, Scottish, and Irish. Its descendant clade I2a2a1a1a1 (L126/S165) is more common in Scotland. Its offshoot I2a2a1a1a1a (S7753) includes men of several surnames of Irish Gaelic origin, such as McGuinness, Callahan, McConville and McManus, indicating that S7753 arrived in Ireland before the development of surnames. The estimated date of the haplogroup is around AD 500, which makes a neat fit to the earliest reference to the Cruithin in AD 552 (see p. 169)." -
Blood of the Celts, p. 170.
P. 169: "The Irish Anals refer to warbands of British people rampaging around Ireland. The earliest reference tells of the 'killing of Colman Mor, son of Diarmaid, in his chariot, by Dubhshlat Ua Treana, one of the Cruithni', in 552."
Were the Suebi ever used as mercenaries against the Gauls by Caesar? It was my understanding that Ariovistus (the king of the Suebi) was attacking Gaulish tribes via invitation from the Gaulish Arverni and Sequani in their conflict with the Aedui. Germanic auxiliaries and foederati that were stationed at Hadrian’s Wall or nearby include the Tungri, Frisii/Frisiavones, Nervii, Baetasii, and Batavi to name a few.
Caesar did enlist Germanic mercenaries against the Gauls (just as he had earlier enlisted Celtic mercenaries against the Germans. The Suebi were an umbrella group that encompassed several other tribes, including the Marcomanni, for instance, and were predominant in central Germany and Bohemia. Caesar did refer specifically to the Suebi.
We can’t really make the claim that I-M223 originated (17,200 years old, TMRCA of 14,500 years ago, source: YFull) with the Suebi when it is found in Britain and Ireland with very specific and diversified subgroups, there are several (actually many more) specific lineages that could represent several different ancestries, even rather aged information here on Eupedia alludes to this:
https://www.eupedia.com/europe/Haplogroup_I2_Y-DNA.shtml#I2a2a
i was referring specifically to Maciamo's I2a2 map. Yes, in SW Scotland and in SE Ulster, those would be downstream clades of P214 (L126/S165 and S7753?). (90% of P214 is M223.)
You’re more likely to find influence from the Angles in pre-Norse Scotland IMO, read:
https://dsl.ac.uk/about-scots/history-of-scots/origins/, it’s also worth mentioning that the sons of Æthelfrith of Bernicia were exiled and sought refuge (with their entourage) in both Dál Riata (Oswald and Oswiu) and Pictland (Eanfrith, who’s own son Talorgan mac Enfret was king of Picts). Here is some reading on Oswald (Oswiu included) and his association with the Gaelic world:
https://www.heroicage.org/issues/4/ziegler.html
There is also mention of later Northumbrian kings who took refuge in Dál Riata or Pictland, although this depended on their affiliations either to Bamburgh or York.
Yes, I've read about that (in
Ancient Scotland by Stewart Ross). There was a very clear distinction between the Angles in Deira and Bernicia (Northumbria) and the Britons (Novantae, Stratheclyde, Lothian, Gododdin, etc.). In Maciamo's map, the highest concentration of I2a2 looks to skirt Bernicia. I suspect the Picts were just backcountry Britons.