Ancient city's collapse

Ancient city's collapse

Credit: Lisa Overholtzer, Wichita State University

New DNA analysis of the bones from 25 individuals in Xaltocan suggest that the population changed after the Aztec conquest.

Ghost town?

Ghost town?

Credit: Lisa Overholtzer, Wichita State University

Colonial records from the 1500s onward suggested that the Otomi people fled the city-state of Xaltocan in 1395 and that it was completely abandoned until 1435, when the Aztecs conquered the city.

Continuous Occupation

Continuous Occupation

Credit: Lisa Overholtzer, Wichita State University

But when Lisa Overholtzer and her colleagues excavated the site, they found evidence for continuous occupation, belying the tales found in historic documents. To understand how the people changed after the Aztec conquest, the team analyzed bones and teeth from 25 skeletons buried under two patios in the ancient city.

Genetic shift

Genetic shift

Credit: Lisa Overholtzer, Wichita State University

Using mitochondrial DNA, traces people's maternal lineage, the team found a sharp change in the people occupying those houses before and after the occupation

Changing people

Changing people

Credit: Lisa Overholtzer, Wichita State University

The skeletons, which spanned the period before and after the conquest, suggest that at least some of the Otomi people fled after the fall of the city, or that they radically reorganized themselves in the region.