Using DNA, anthropologists hope to solve the puzzle of what happened to the people of an ancient city-state located in what is now Mexico. The city, Xaltocan, became part of an alliance that eventually grew and became the Aztec empire. But what happened to the Otomí people who lived there "is an anthropological cold case," Nature News says.
Researchers led by Deborah Bolnick at the University of Texas examined DNA from 25 people who lived three houses in the city between 1240 and 1521 — before and after the Aztecs took over. "Our results indicate that the residents of these houses before and after the Aztec conquest have distinct haplotypes that are not closely related, and the mitochondrial compositions of the temporal groups are statistically different," Bolnick and her colleagues report in the American Journal of Physical Anthropology.
Lead author Jaime Mata-Míguez tells Nature News that a number of scenarios are consistent with their findings — the Aztecs could have replaced the Otomí, the elite Otomí may have left and other members of the community moved in, or there was a change in how households were inherited. “We originally thought the question was simply a matter of whether the population was replaced or not,” Mata-Míguez says. “Now we have even more research questions, not just about the site, but about households in the site.”