Eighteen ancient samples from Atajadizo provide a modest but evocative genetic window into the population that inhabited this coastal landscape between 650 and 1650 CE. Paternal lineages are dominated by haplogroup Q (9 of 18 Y-chromosomes), a lineage widely associated with Indigenous peoples of the Americas. Maternal lineages are overwhelmingly Indigenous in character: A2 (8 samples), B2 (4), C (4), with single instances of A (not A2) and D1. These mitochondrial haplogroups (A2, B2, C, D1) are canonical markers of Native American maternal ancestry and align the Atajadizo individuals with broader pre-Columbian populations of the Caribbean, northern South America, and Mesoamerica.
Within this dataset, the genetic picture suggests substantial Indigenous continuity over the sampled interval. The prominence of haplogroup Q on the Y-chromosome may reflect male-line continuity or founder effects in local lineages. Maternal diversity (multiple mtDNA clades) points to varied maternal origins within an Indigenous genetic pool. However, caution is required: 18 samples represent a modest sample size, unevenly distributed across three centuries. Absence of European- or African-associated haplogroups in this set does not preclude later admixture elsewhere on the island—archaeological and historical records show dramatic demographic shifts after 1492 CE. Thus, while the Atajadizo genetic profile strongly reflects Indigenous American ancestry, broader population histories will require larger, temporally targeted datasets to resolve contact-era dynamics and post-contact admixture.