Most “old hands” in the discipline of historical population genetics remember when grand narratives were constructed out of Y chromosomal haplogroup distributions. One of the most distinctive ones is that of haplogroup R1b, which exhibits very high frequencies in the west of Europe, as high as more than 80% among the Basques. Because the Basques are the only non-Indo-European population which exists today in Western Europe, it was presumed that they are more ancient than other groups. And, their high frequency of R1b (along with other peculiarities such as a high frequency of Rh-), was taken to indicate that they reflected the genetics of Europe’s aboriginal hunter-gatherers when farming arrived.
This turned out to be wrong in a lot of details. Genetically the Basques are quite like the European farmers from Anatolia who replaced the original hunter-gatherers. Less so than the Sardinians, as they have more hunter-gatherer ancestry. But instead of being the language of European hunter-gatherers, it seems plausible that the Basque language descends from that of the Cardial culture.