Assessing temporal and geographic contacts across the Adriatic Sea through the analysis of genome-wide data from Southern Italy.

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. • Complex interactions between the two sides of the Adriatic Sea unveiled from the genomes of present-day Southern Europeans • Uneven affinity between Neolithic Greeks and Southern Italians confirms the importance of post-Iron Age demographic events. • Shared Iran Neolithic-related ancestry suggests gene flows along the Mediterranean Sea shores that started in the Bronze Age. • Putatively adaptive signals in Northern and Southern Italians associated with alcohol metabolism and immunological traits. [ABSTRACT FROM AUTHOR]