Maize had a Complex Path Into the American Southwest

After it was first domesticated from the wild teosinte grass in southern Mexico, maize, or corn, took both a high road and a coastal low road as it moved into what is now the U.S. Southwest, reports an international research team that includes a UC Davis plant scientist and maize expert.

The study, based on DNA analysis of corn cobs dating back over 4,000 years, provides the most comprehensive tracking to date of the origin and evolution of maize in the Southwest and settles a long debate over whether maize moved via an upland or coastal route into the U.S.

Study findings, which also show how climatic and cultural impacts influenced the genetic makeup of maize, will be reported Jan. 8 in the journal Nature Plants.

The study compared DNA from archaeological samples from the U.S. Southwest to that from traditional maize varieties in Mexico, looking for genetic similarities that would reveal its geographic origin.

"When considered together, the results suggest that the maize of the U.S. Southwest had a complex origin, first entering the U.S. via a highland route about 4,100 years ago and later via a lowland coastal route about 2,000 years ago," said Jeffrey Ross-Ibarra, an associate professor in the Department of Plant Sciences.

The study further provided clues to how and when maize adapted to a number of novel pressures, ranging from the extreme aridity of the Southwest climate to different dietary preferences of the local people.

Excavations of multiple stratigraphic layers of Tularosa cave in New Mexico allowed researchers to compare genetic data from samples from different time periods.

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Maize Consumption in pre-Hispanic Andes

Maize consumption in pre-Hispanic south-central Andes: chemical and microscopic evidence from organic residues in archaeological pottery from western Tinogasta (Catamarca, Argentina)

Authors:

Lantos et al

Abstract:

Pre-Hispanic Andean societies depended economically on the cultivation of maize (Zea mays), the main staple food crop in the region after its introduction from highland Mexico. Here we report new data from residue analysis of potsherds recovered in archaeological sites in western Tinogasta, Catamarca province, Argentina, ca. 3rd to 16th centuries AD. Molecular and isotopic (δ13C values) compositions of fatty acids and microscopically identified maize starch granules from organic residues absorbed in archaeological potsherds were compared with Andean ingredients and food residues obtained from experimental replica pots, where traditional recipes were cooked. Complex mixtures of lipids and starch remains observed in archaeological cooking pots indicated combinations of Andean ingredients such as llama, beans, algarroba, and maize, and suggest continuity in the domestic foodways through time. The distribution and δ13C values of lipids preserved in vessels used for alcoholic beverage preparation, storage and transport in Inka sites suggested the possible consumption of two drinks with distinct patterns: traditional Andean maize beer (chicha) and a local fermented drink made from algarroba flour (aloja). This is potential evidence for consumption practices in festive contexts sponsored by the Inka state.