DNA analysis in the last few decades has proved that today's Sardinians are very, very close to the original inhabitants of Europe before Aegean Farmers arrived (which was also well before the Indo-Europeans arrived). In fact, native Sardinians are the least admixed people in Europe. I don't at all agree with you that Italians as a whole are excessively admixed with extra-European genes or bad genes -- though I do, of course, believe that _all_ White nationalities could do with a healthy dose of eugenics, not only to address undesirable admixture but to counteract centuries of dysgenic breeding.