"A second important haplogroup, which accounts for about 18% of the Sardinian variability, is R1b1a2 (R-M269) that has been related to the pre-Neolithic heritage of Sardinia (Contu et al. 2008; Morelli et al. 2010) for its large prevalence in western Europe. It is differentiated in a large number of sub-haplogroups that could have followed different pathways, such as, for example, R-U152, the most frequent lineage in central and northern Italy, which could reflect ancient contacts with the Etruscan people. The Palaeolithic origin of this haplogroup has been challenged by some aDNA studies that indicated its earliest origin in the YSP from eastern Europe (Haak et al. 2015), but more recently it has been detected in one Palaeolithic individual from Villabruna (northern Italy), indicating a much earlier origin and diffusion of this haplogroup (Fu et al. 2016).
Other Sardinian founding lineages may have arrived on the Island from other areas and with a different timing, but not related to the spread of the agriculture from the fertile crescent. The sub-haplogroup G2a, which accounts for about 11% of the Sardinian sample is very important for its phylogeographic distribution, rooted in the Caucasus and diffused in Europe through the Danubian route of Neolithisation. In particular, the founder lineage defined by the presence of L-91 SNP shows a peak in northern Sardinia – southern Corsica and a noticeable occurrence in Tuscany and in Tyrol, including the Bronze Age mummified individual known as Oetzi (Keller et al. 2012), possibly indicating a crossing of the Alps and subsequent arrival in the Mediterranean islands. The STR variation is higher in north Sardinia than in south Corsica, possibly indicating a migration of Nuragic people who introduced the Torrean culture to the neighbouring island (Grugni et al. 2019)."