As implied above (McGrath of Harlow), genetics and culture are two totally different things. Most scholars do not consider the Celts as a race at all but as a cultural grouping; so whatever is happening to the genetic populations can be separate to whatever is happening to the "cultural Celts".
I have come across the view (supported by sources such as Dr Anne Ross and Peter Beresford Ellis) that Celtic art and culture spread from (central) Europe into Britain and Ireland and that the invading "Celts" killed or intermarried with the native population, suggesting a link between "genetic" and "cultural" Celts. An alternative view, supported by Simon James and Barry Cunliffe, suggests that, although Celtic culture spread across Europe, the Continental Celts did not physically replace the existing populations.
Genetic studies clearly support the view of a common genetic heritage for what is referred to as the Atlantic façade (Northern Spain, Brittany, Cornwall, Wales and Ireland and to a lesser extent the rest of southern Britain [but much less other parts of the British Isles]. [Am J Hum Genet. 2004 October; 75(4): 693–702. Published online 2004 August 12]. The evidence suggests "a distinctive Atlantic genetic heritage with roots in the processes at the end of the last Ice Age" for these Atlantic façade Celts. The migration routes would have been maritime, much easier at that time than across forested countryside.
This would suggest that there is indeed a genetic link between Ireland and the rest of the Atlantic façade, (rather than with Northern Britain, Scotland and central Europe). Presumably the Viking origins of Dublin are an anomaly!? However none of this negates the likelihood of a cultural heritage for the Celts originating in Central Europe.
So is music cultural or genetic?