Population level comparisons in central Mexico using cranial nonmetric traits

Area of Science:

• Bioarchaeology
• Paleogenetics
• Population Genetics

Background:

• Investigating the genetic relationships between Classic Teotihuacan and its contemporary settlements is crucial for understanding regional population dynamics.
• Previous hypotheses suggested that neighboring towns were populated by inhabitants of Teotihuacan following its collapse.

Observation:

• Cranial nonmetric traits from 280 adult skulls spanning the Preclassic to Postclassic periods were analyzed.
• Samples included Classic Teotihuacan sites (La Ventilla, San Sebastián Xolalpan) and surrounding regions (Xaltocan, Toluca valley, Mogotes, Xico).
• Statistical analysis employed a parametric bootstrap for the mean measure of divergence.

Findings:

• Significant biodistance was observed between Classic Teotihuacan and its neighbor villages, indicating genetic separation.
• Samples from Xico showed minimal genetic change from the Preclassic to Postclassic periods.
• Los Mogotes samples displayed context-dependent variation, with household burials differing from ceremonial interments.

Implications:

• The genetic distinctiveness of Teotihuacan and its neighbors challenges the traditional view of population resettlement after Teotihuacan's decline.
• This study highlights the persistence of independent population identities in central Mexico during the Classic and Epiclassic periods.
• Findings contribute to a nuanced understanding of social and demographic processes in Mesoamerican urbanism.