Southern Italy was characterised by a complex prehistory that started with different Palaeolithic cultures, later followed by the Neolithization and the demic dispersal from the Pontic-Caspian Steppe during the Bronze Age. Archaeological and historical evidences point to a link between Southern Italians and the Balkans still present in modern times. To shed light on these dynamics, we analysed around 700 South Mediterranean genomes combined with informative ancient DNAs. Our findings revealed high affinities of South-Eastern Italians with modern Eastern Peloponnesians, and a closer affinity of ancient Greek genomes with those from specific regions of South Italy than modern Greek genomes. The higher similarity could be associated with a Bronze Age component ultimately originating from the Caucasus with high Iranian and Anatolian Neolithic ancestries. Furthermore, extremely differentiated allele frequencies among Northern and Southern Italy revealed putatively adapted SNPs in genes involved in alcohol metabolism, nevi features and immunological traits.
This paper finally seems to straightout admit that the statistics for using Greeks as a donor population can be messed up by Slavic migration. There’s heterogeneity though. For example, Maniotes are good donors to eastern Sicily. Maniotes are famous for having been pagan until the 800’s, because their godforsaken peninsula was so isolated from the rest of the world. And, in these data they seem to have less Slavic ancestry, which is what you’d expect if they were so isolated.