van de Loosdrecht (2020): Genomic and dietary shifts in Sicilian prehistory

Miscellanea DNA in the News van de Loosdrecht (2020): Genomic and dietary shifts in Sicilian prehistory

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  • #27946
    Carlos Quiles
    Keymaster

      Genomic and dietary transitions during the Mesolithic and Early Neolithic in Sicily by van de Loosdrecht et al. bioRxiv (2020), https://doi.org/10.1101/2020.03.11.986158.

      Abstract:

      Southern Italy is a key region for understanding the agricultural transition in the Mediterranean due to its central position. We present a genomic transect for 19 prehistoric Sicilians that covers the Early Mesolithic to Early Neolithic period. We find that the Early Mesolithic hunter-gatherers (HGs) are a highly drifted sister lineage to Early Holocene western European HGs, whereas a quarter of the Late Mesolithic HGs ancestry is related to HGs from eastern Europe and the Near East. This indicates substantial gene flow from (south-)eastern Europe between the Early and Late Mesolithic. The Early Neolithic farmers are genetically most similar to those from the Balkan and Greece, and carry only a maximum of ~7% ancestry from Sicilian Mesolithic HGs. Ancestry changes match changes in dietary profile and material culture, except for two individuals who may provide tentative initial evidence that HGs adopted elements of farming in Sicily.

      One-sentence summary

      Genome-wide and isotopic data from prehistoric Sicilians reveal a pre-farming connection to (south-) eastern Europe, and tentative initial evidence that hunter-gatherers adopted some Neolithic aspects prior to near-total replacement by early farmers.

      Best summary image of the transition IMHO:

      Sicily ancestry Mesolithic - Neolithic

      Genomic affinity of the ancient Sicilians. (A) Comparing the ancestry in Sicily 386 EM and LM HGs to various West Eurasian HGs (X), as measured by f4(Chimp, X; Sicily EM HGs, Sicily LM HGs). Cooler colours indicate that X shares more genetic drift with Sicily EM HGs than with Sicily LM HGs, and warmer colours indicate the opposite. Dot sizes reflect |z|-scores. Not plotted: AfontovaGora3 (f4 = 0.0023, z = 3.73), BerryAuBac (f4 = 0.0063, z = 5.10). Whereas Upper Palaeolithic and Mesolithic HGs from western Europe, including Villabruna cluster individuals, are genetically closer to Sicily EM HGs, those from eastern Europe are closer to Sicily LM HGs. (B) Early Neolithic Sicilian farmers show high genetic affinity to contemporaneous farmers from the Balkan (Croatia and Greece EN Peloponnese), as measured by f3(Mbuti; Sicily EN, X). Warmer colours indicate higher levels of allele sharing. Error bars in the bar plot indicate 1 SE.

      #27955
      Carlos Quiles
      Keymaster

        Interestingly, the paper also supports some main points:

        1. The WHG-reated migration might have been initially mediated by R1b-rich Epipalaeolithic groups from south-eastern Europe, but it seems to have been soon hijacked by I2 lineages, much like the later Neolithic migrations.

        The two Neolithic-related reported Y-DNA show what seems like a resurgence or continuity of previous Mesolithic lineages, C1a2, but also likely Neolithic H. Despite the low number of samples, it questions the origin of the R1b-V88 expansion into Africa from (NW) Sicily.

        See more on the question of the R1b-V88 expansion.

        2. The affinity of Impressed Ware and Stentinello I to Balkan Neolithic- or Greek Neolithic-related  ancestry supports that the NW Anatolia Neolithic-related ancestry found among sampled Italics and Etruscans could be in fact an admixture of “local” peoples from Southern Italy or the Adriatic, in line with the appearance of the Etruscan J2b-L283.

        See more on the EEF ancestry of Italics and Etruscans.

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