The Purviance Line is the most widely Y-DNA tested Ireland-surname line in the world. As of March 2021, at least 23 tested men are believed to be members of this line.
Based on multiple Big Y tests, the line descends from the R1b L21 subclade, often referred to as the "Atlantic Celtic" branch:
- From Eupedia: "The Proto-Italo-Celto-Germanic R1b people had reached in what is now Germany by 2500 BCE. By 2300 BCE they had arrived in large numbers and founded the Unetice culture. Judging from the propagation of bronze working to Western Europe, those first Indo-Europeans reached France and the Low Countries by 2200 BCE, Britain by 2100 BCE and Ireland by 2000 BCE, and Iberia by 1800 BCE. This first wave of R1b presumably carried R1b-L21 lineages in great number (perhaps because of a founder effect), as these are found everywhere in western, northern and Central Europe. Cassidy et al. (2015) confirmed the presence of R1b-L21 (DF13 and DF21 subclades) in Ireland around 2000 BCE. Those genomes closely resembled those of the Unetice culture autosomally, but differed greatly from the earlier Neolithic Irish samples. This confirms that a direct migration of R1b-L21 from Central Europe was responsible for the introduction of the Bronze Age to Ireland."