Agriculture first reached the Iberian Peninsula around 5700 BCE. However, little is known about the genetic structure and changes of prehistoric populations in different geographic areas of Iberia. ...In our study, we focus on the maternal genetic makeup of the Neolithic (~ 5500-3000 BCE), Chalcolithic (~ 3000-2200 BCE) and Early Bronze Age (~ 2200-1500 BCE). We report ancient mitochondrial DNA results of 213 individuals (151 HVS-I sequences) from the northeast, central, southeast and southwest regions and thus on the largest archaeogenetic dataset from the Peninsula to date. Similar to other parts of Europe, we observe a discontinuity between hunter-gatherers and the first farmers of the Neolithic. During the subsequent periods, we detect regional continuity of Early Neolithic lineages across Iberia, however the genetic contribution of hunter-gatherers is generally higher than in other parts of Europe and varies regionally. In contrast to ancient DNA findings from Central Europe, we do not observe a major turnover in the mtDNA record of the Iberian Late Chalcolithic and Early Bronze Age, suggesting that the population history of the Iberian Peninsula is distinct in character.
...its application for the analysis of enclosures and grave fillings or other structures of anthropogenic origin is less common. ...in order to apply them to our particular case, it was necessary to ...carry out intensive sampling in addition to possessing extensive geological knowledge of the site, which must meet the appropriate natural conditions. ...on the surface, the filling culminates with sediment of anthropogenic and archaeological materials: many pottery sherds, two pedunculated flint arrowheads, some faunal remains and many bone artefacts, some charcoal, and several mud fragments. ...regarding the methodology and analyses, we must conclude that, in our opinion, the sedimentological studies are essential tools and indicators when interpreting the filling processes of enclosures. ...we must be sure that the base on which the site is located corresponds to a natural geological soil accumulation. ...sedimentological analyses help us to put forward correct interpretations in relation to the not-always-easy interpretation of these negative structures fillings, especially in ditched enclosures, where natural and single events determine the use and silting processes of these enigmatic structures.
Western Eurasia witnessed several large-scale human migrations during the Holocene
. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes-mainly ...from the Mesolithic and Neolithic periods-from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a 'great divide' genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 BP, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 BP, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a 'Neolithic steppe' cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
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