SUBSISTENCE

Teosinte Becomes Maize

~9,000 years ago

Neolithic · Neolithic · Holocene · Greenlandian

Maize has a wild ancestor so unlike it that botanists argued for a century: teosinte, a Mexican grass whose hard little ears hold a dozen armored kernels. Genotyping of hundreds of plants settled the question: all maize descends from a single domestication in southern Mexico around 9,000 years ago, diversifying first in the highlands before spreading along two great paths across the Americas. Ancient cobs show the transformation still incomplete millennia later.

Why it matters

No crop was engineered further from its ancestor by ordinary selection: teosinte's stony fruitcase ears became the naked, swollen, human-dependent cob, a plant that can no longer seed itself. Maize fed the Olmec, Maya, Aztec and Inca worlds and, after 1492, much of the old one. It is the American half of the answer to what farming did to our species.

Dating & uncertainty

The ~9,000 year date is genetic: microsatellites across maize landraces point to a single domestication in southern Mexico around then. The oldest physical cobs, from Guilá Naquitz, are younger, about 6,200 years, and 5,300-year-old cobs from Tehuacán were still only partial domesticates, so the plant's remaking was far from instant.

Sources

1. Matsuoka et al. (2002), PNAS · A single domestication for maize shown by multilocus microsatellite genotypingdoi:10.1073/pnas.052125199
2. Benz (2001), PNAS · Archaeological evidence of teosinte domestication from Guilá Naquitz, Oaxacadoi:10.1073/pnas.98.4.2104
3. Vallebueno-Estrada et al. (2016), PNAS · The earliest maize from San Marcos Tehuacán is a partial domesticate with genomic evidence of inbreedingdoi:10.1073/pnas.1609701113

Our species’ history as one day

23:18:5141 min 9 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day