Echoes of Chalcolithic Portugal

The Portugal_C assemblage sits squarely within the Chalcolithic — a cinematic threshold when copper tools, monumental tombs and large ritual enclosures reshaped Iberia's landscapes. Archaeological data indicates activity at key sites included in this set: the megalithic tholos of Paimogo I (Lourinhã), the subterranean gallery of Almonda (Galeria da Cisterna), the ritual ditched enclosure of Perdigões (Reguengos de Monsaraz), and cave burials at Monte Canelas and Cova das Lapas. These places, dated between 3352 and 2153 BCE, reflect a network of funerary and ritual practice rather than a single, uniform culture.

Material culture — pottery styles, monumental mortuary architecture, and evidence for long-distance exchange — points to local development built on earlier Neolithic traditions. Limited evidence suggests regional continuity of population rather than wholesale population replacement: the persistence of certain maternal lineages and the dominance of a Y-DNA profile consistent with earlier European lineages hint at deep local roots. At the same time, archaeological indicators of new social complexity — forced/organized labor to build tombs, curated grave offerings, and signs of increased inequality — mark the Chalcolithic as a period of social transformation in western Iberia.

Eighteen individuals compose the Portugal_C genetic sample — a modest but informative window into Chalcolithic demography. Y-chromosome data are dominated by haplogroup I (9 individuals) with a single G. The prevalence of I echoes patterns seen in other Iberian ancient populations, where I lineages (often I2 in other datasets) are associated with long-term European ancestry and suggest substantial local male continuity. The presence of G — commonly linked to early Neolithic farmer expansions elsewhere in Europe — in one individual points to lingering farmer-associated paternal ancestry but is too rare here to indicate a major incoming male migration.

Mitochondrial diversity includes U (4), J (3), K (3), H (3) and a single H1. U maternal lineages are frequently connected to earlier hunter-gatherer ancestry, while J, K and H are common among Neolithic and Chalcolithic farming populations. Together, these maternal markers suggest admixture between indigenous Mesolithic-descended groups and farmer-descended communities. Notably, the absence or low frequency of Steppe-associated Y haplogroups (e.g., R1b) in this set suggests limited male-mediated Steppe influx into these sampled locales during 3352–2153 BCE; however, this conclusion is preliminary because patterns can vary across regions and cemetery-based sampling can bias results. With 18 samples, broad trends are discernible, but sub-haplogroup resolution and low-count categories (G = 1, H1 = 1) require cautious interpretation.