Since 2006 genetics has gotten very deeply involved in the origins of the Etruscans, a non-Indo-European group in ancient Italy often termed “mysterious” for a reason. The two dominant models of their origins in antiquity, and the present, involve a Near Eastern influence, or a totally indigenous one. Since genetics originally came down on the side of at least a partial Near Eastern origin in 2006 the argument has gone back and forth. A new paper in PLOS ONE seems to lend some tentative support for an external influence, Mitogenomes from The 1000 Genome Project Reveal New Near Eastern Features in Present-Day Tuscans. Because the mitochondrial genome has been widely sampled geographically the authors managed to compare the lineages of Tuscans to many other populations, and it turns out that a small minority are surprisingly clustered with populations in the South Caucasus. They really couldn’t put a good time peg on the result, but it strikes me that the peculiarity of this association in Tuscany in particular suggests that this region was influenced by a specific Near Eastern group which did not settle the rest of Italy, which was mostly inhabited by various Indo-European groups at that point. In Spain the possible non-Indo-European group, the Iberian languages, are mostly in the south with the exception of that of the Basques. The possibility of ancient Sardinian as non-Indo-European also makes sense in light of that island’s isolation.
From the most recent work on the genetics of likely Indo-European groups it seems possible that arrival of these people to Southern Europe probably occurred on the order of 3 to 4 thousand years ago. The persistence of a non-Indo-European substrate in Tuscany, as opposed to other regions of mainland Italy, seems rather strange if that timing is is correct. Probably the ultimate answers are going to be found with IBD autosomal segment analyses, as in the Peter and Coop paper from a few years back, but with large world-wide sample sizes and regional coverage.