The Irish are Not Celts

[oudysseos]

Actually the TCD study that the OP quoted did in fact consider y-chromosome DNA as well, as did the Sykes book and I believe the Oppenheimer book. The conclusion was more or less the same: not much genetic evidence for massive, genocidal invasions of Continental Celts in the British Isles.

I have to point out that the whole invasion model is very old, coming from various mythological sources and transmitted through the Book of Leinster and the Book of Invasions. It has been a while since anybody took the Fir Bolgs, Fomorians and Tuatha de Dannan seriously.

Doesn't mean the Irish weren't Celts themselves.