Genetic analysis reveals kinship in ancient Moche sacrifice

Harvard University-led researchers investigated an elite Moche burial group at Huaca Cao Viejo, uncovering new details on kin-based status within Moche society. The evidence centers on four generations of a family dated to approximately 500 CE, with genetic data connecting the Señora de Cao to a sibling, a grandparent, and two sacrificed juveniles.

Moche culture thrived along Peru’s North Coast between the 4th and 10th centuries CE, constructing monumental adobe temples (huacas) and complex irrigation networks. Previous archaeological work has hypothesized kinship as a factor in high status and political influence.

Genomic evidence was required to verify whether Moche elites were indeed buried with close relatives and whether sacrificial victims shared direct biological ties with principal tomb occupants.

In the study, “Family relations of Moche elite burials on the North Coast of Peru (~500 CE): Analyses of the Señora de Cao and relatives,” published in PNAS, researchers set out to confirm or reject earlier hypotheses.

Examination of pyramid-like tomb structures in the Chicama Valley revealed six individuals placed in four burials. Investigators extracted and sequenced ancient DNA from the teeth and bones of all six individuals. Radiocarbon dating places five of those remains around 500 CE, while one grandparent figure predated the others by several decades and was likely reburied to accompany the group.

Stable isotope ratios of carbon, nitrogen, oxygen, lead, and strontium established dietary patterns and geographic origins.

Analysis of carbon isotopes indicated that most elite group members consumed a diet heavily reliant on C4 plants, such as maize, constituting approximately 70% of their plant intake. Nitrogen isotope ratios suggest that their protein intake included substantial amounts of marine protein, estimated between 45% to 70%.

Strontium isotope ratios (87Sr/86Sr) for most members of the elite group aligned with local values consistent with the Chicama Valley. The sacrificed juveniles exhibited distinct strontium ratios that diverged from the local values, indicating origins from a different geographic region.

Lead isotope ratios reinforced this finding, with one of the juveniles (called B3s) presenting as an extreme outlier compared to the other individuals, further supporting her nonlocal origins. Oxygen isotope ratios for B3s were relatively low, consistent with an inland or highland upbringing.

B3s contrasts with the others, who all showed signatures of residence near the Chicama Valley. Without genetic evidence, this might suggest that B3s was unrelated to the others.

Genetic results confirmed close ties among the individuals, including a sibling relationship between an adult male and the Señora and a parent-child link between that male and his sacrificed son.

source