I don't think this is credible. (And in some places it's semi-crazy.) Just off the top of my head, the population that has the most DNA in common with Neanderthals is not Basques but Tuscans. This article summarizes a much more plausible theory: <a href="https://www.bbc.com/news/science-environment-34175224" rel="nofollow">https://www.bbc.com/news/science-environment-34175224</a>
Seems another case of nationalism needs myths, so lets build some to explain why are the choosen ones.<p>The article don't even knows where to locate the basque region in the map