The image above is adapted from the 2010 paper A Predominantly Neolithic Origin for European Paternal Lineages, and it shows the frequencies of Y chromosomal haplogroup R1b1b2 across Europe. As you can see as you approach the Atlantic the frequency converges upon ~100%. Interestingly the fraction of R1b1b2 is highest among populations such as the Basque and the Welsh. This was taken by some researchers in the late 1990s and early 2000s as evidence that the Welsh adopted a Celtic language, prior to which they spoke a dialect distantly related to Basque. Additionally, the assumption was that the Basques were the ur-Europeans. Descendants of the Paleolithic populations of the continent both biologically and culturally, so that the peculiar aspects of the Basque language were attributed by some to its ancient Stone Age origins.
As indicated by the title the above paper overturned such assumptions, and rather implied that the origin of R1b1b2 haplogroup was in the Near East, and associated with the expansion of Middle Eastern farmers from the eastern Mediterranean toward western Europe ~10,000 years ago. Instead of the high frequency of R1b1b2 being a confident peg for the dominance of Paleolithic rootedness of contemporary Europeans, as well as the spread of farming mostly though cultural diffusion, now it had become a lynch pin for the case that Europe had seen one, and perhaps more than one, demographic revolutions over the past 10,000 years.
This is made very evident in the results from ancient DNA, which are hard to superimpose upon a simplistic model of a two way admixture between a Paleolithic substrate and a Neolithic overlay. Rather, it may be that there were multiple pulses into a European cul-de-sac since the rise of agriculture from different starting points. We need to be careful of overly broad pronouncements at this point, because as they say this is a “developing” area. But, I want to go back to the western European fringe for a moment.