Sicily: from fifteen millennia ago to present

Sicily, the biggest isle in the Mediterranean, may be best known for its incredible food and splendid panoramas, but there is much more to it. The isle has a strategical central position in "Mare Nostrum", as one of its conquerors called the Mediterranean Sea, and has always been a bridge between Africa and Europe, between what was "East" and "West" in Western Eurasia for many millennia. A role that is also reflected in Sicilians themselves, as shown by the new paper "Fifteen millennia of human mitogenome evolution in Sicily", on the prestigious journal Science Advances and authored by a coalition of Italian Universities.

The work focuses on recollecting the story of Sicily from a maternal point of view, by analyzing how mitochondrial DNA (mtDNA), the circular DNA of the "powerhouse of the cell", is transmitted from mother to child along time in a matrilinear unbroken chain. Like in the Telephone game, sometimes the information slightly changes and as such is transmitted to the child: a new chain or lineage begin. Researchers amassed 116 ancient mtDNAs from several archaeological sites, with the oldest individual from approximately 13,000 BC, encompassing all known and unknown populations that set foot in Sicily: from the hunter-gatherers of Paleolithic to the Medieval Islamics, passing through Sicanians, Phoenicians, Greeks, Romans and medieval Christians. To broaden the visual, they also sampled 236 living Sicilians across the whole island, dividing them into groups by geographical and political borders.

Analyses of mtDNA lineages (haplogroups) shows that modern individuals can be modeled as sole Sicilian population with the majority of lineages from Western Eurasia, but to the surprise of researchers, a robust minority of African haplogroups, from both North Africa and sub-Sahara. Looking also at ancient individuals, this connection is present even before the arrival of Phoenicians and continues through the Iron Age, the Roman period and Medieval times, showing a constant exchange between the continent and the isle.

That is not the only thing that ancient DNA helped to reveal. Hunter-gatherers from Paleolithic had particular haplogroups, like U5b, that subsequently disappeared or dropped dramatically in percentage. Afterwards, the various populations that reached Sicily brought their own haplogroups, leading to the rich landscape visible in modern people. Researchers investigated by testing several archeological models that could explain their data, thus revealing that Sicilian population changed in the passage from Paleolithic to Neolithic with the arrival of farmers from Anatolia and then there was a continuity with contacts and exchanges with Phoenicians, Greeks, and many other Mediterranean groups.

To quantify the change in population, the authors identified haplogroup markers from Sicilian hunter-gatherers and Anatolian farmers and then simulated their population size through time. Hunter-gatherers U5b reached its peak 10,000 years ago, and then started to decline. Almost at the same time, Neolithic farmers U8b/K started increasing. The joint decrease-increase lasted 3 millennia, signifying a long period in which the two populations cohabited Sicily. Farmers diffused slowly in the island, a fact also testified by the gradual diffusion of their domesticated plants, as shown by botanical archeology.

So, Sicily first was inhabited from hunter-gatherers from the whole of Europe, then came Anatolian farmers that partially and slowly substituted them. In the following millennia, each group enriched the mosaic with their own tiles, without destroying the work that was there before, leading to the variety and richness in maternal lineages present today. In conclusion, this study about the maternal history of Sicily reveal something that Sicilians love to say about themselves and their beautiful island: in Sicily people met, mixed and transformed.