Paso del Indio Ceramic People

Along the river terraces of Vega Baja, the Paso del Indio site holds stratified deposits that capture centuries of Islander life. Archaeological data indicate a Ceramic-period occupation stretching roughly from the mid-first millennium CE through the late second millennium (here represented by radiocarbon and stratigraphic dates spanning 650–1400 CE). The material culture—pottery temper, decoration styles, and curated tools—ties these communities into broader Greater Antilles Ceramic traditions, reflecting patterns of migration, interaction, and local adaptation.

Genetic data from eight individuals recovered at Paso del Indio begin to fill a molecular portrait of this emergence. Limited evidence suggests a predominance of Native American paternal lineages (Y-haplogroup Q) alongside maternal lineages dominated by mtDNA clades A and C. These signals are consistent with deep pre-contact Indigenous ancestry across the Caribbean, but with only eight genomes the broader demographic story—timing of arrivals, the extent of continuity, and links to neighboring islands—remains provisional. Archaeology anchors the narrative in place and time; aDNA provides familial and population-scale threads that must be woven carefully, with clear attention to sampling limits and post-depositional processes.

Eight ancient individuals from Paso del Indio provide an initial genetic snapshot of Ceramic-period Puerto Rico. Y-chromosome haplogroup Q is observed in four samples, a lineage widely associated with Indigenous peoples of the Americas and consistent with regional paternal continuity. On the maternal side, mtDNA haplogroups C and A are common in Native American populations: three individuals carry haplogroup C, two carry A (including two classified specifically as A2), and one carries a sub-lineage labeled A2e. These maternal lineages are typical of pre-contact Caribbean and continental populations, indicating deep connections to broader Indigenous gene pools.

Caveats are essential. A total sample size of eight is small: any population-level inference must be treated as preliminary. The observed haplogroup counts may reflect local kin groups, sampling bias, or preservation-mediated survival of particular burials. Genome-wide analyses (autosomal ancestry, runs of homozygosity, and admixture modelling) are required to resolve questions about effective population size, connectivity with other islands, and potential gene flow from mainland South America or Central America. Still, the concordance between archaeological context and these Native American haplogroups supports continuity hypotheses and demonstrates how even limited aDNA can powerfully complement archaeological narratives.