Irish Celebrity Girl

The frequency of Y-DNA haplogroup R1b (the most common haplogroup in Europe) is highest in the populations of Atlantic Europe and, due to European emigration, in North America, South America, and Australia. In Ireland and the Basque Country its frequency exceeds 90% and approaches 100% in Western Ireland. The incidence of R1b is 70% or more in Celtic regions - Cumbria and Cornwall in England, northern Iberia (Celtic - Galicia (Spain) and Basque Country ), western France (Celtic - Brittany), and Celtic Countries - Wales and Scotland in Britain. R1b's incidence declines gradually with distance from these areas but it is still common across the central areas of Europe. R1b is the most frequent haplogroup in Germany, and is common in southern Scandinavia and in Italy. This led to writers, such as Stephen Oppenheimer and Bryan Sykes, to conclude that the majority of Irish people (and indeed all natives of the British Isles) primarily descend from an "Iberian refugium" population bottleneck dating back to the last ice age.
However, this haplogroup is now believed by some to have originated over 12,000 years more recently than previously thought. It thus follows that Irish and many other R1b subclades will be considerably younger than the maximum age of 18,000 years. The previous estimates, based on inaccurate dating methods (30,000+ years BP), made R1b and its subclades seem to be more useful indicators of the paleolithic era populations of western Europe than they actually are. According to recent 2009 studies by Bramanti et al. and Malmström et al. on mtDNA, related western European populations appear to be largely from the neolithic and not paleolithic era, as previously thought. There was discontinuity between mesolithic central Europe and modern European populations mainly due to a extremely high frequency of haplogroup U (particularly U5) types in mesolithic central European sites.
That there exists an especially strong genetic association between the Irish and the Basques, one even closer than the relationship between other west Europeans, was first challenged in 2005, and in 2007 scientists began looking at the possibility of a more recent Mesolithic- or even Neolithic-era entrance of R1b into Europe. A new study published in 2010 by Balaresque et al. implies either a Mesolithic- or Neolithic- (not Paleolithic) era entrance of R1b into Europe. However, all these genetic studies are in agreement that the Irish and Basque (along with the Welsh) share the highest percentage of R1b populations. Although the Welsh have a greater presumed Neolithic input than both the Irish and the Basques. Genetic marker R1b averages from 83-89% amongst the Welsh.