A study published in the American Journal of Human Genetics in 2005 entitled A Y Chromosome Signature of Hegemony in Gaelic Ireland describes how researchers sampled DNA from about 800 men from across Ireland and seem to have found genetic evidence in Northwestern Ireland which supports the idea that the historical ruling family of Ireland from the 7th through the 11th centurys (the O'Neills) may indeed be descendants of the 'mythological' Niall of the nine hostages as their name suggests (literally 'descendants of Niall'). For the biologically minded, you can download the article in PDF here.

Historians have long suspected that the Irish myths may contain accounts of real historical events distilled through time and retelling, and that the long lists of relations in the myths may turn out to be genealogically accurate to some degree. This study seems to suggest that thinking is correct.

A Y Chromosome Signature of Hegemony in Gaelic Ireland
Am. J Hum. Genet., 78: 334–338, 2006
Laoise T. Moore,1,Brian McEvoy,1,Eleanor Cape,1 Katharine Simms,2 and Daniel G. Bradley1
1Smurfit Institute of Genetics and 2School of Histories and Humanities, Trinity College, Dublin
Received September 29, 2005; accepted for publication November 18, 2005; electronically published December 8, 2005.