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.
