Heavy metals and evolution at Tehuacan 
Origin and evolution of maize, heavy metals as catalyst of the evolutionary process

    Since the last century, several theories have been proposed to explain the origin and evolution of maize, the most popular of them accepts teosinte Zea mays ssp mexicana as the direct ancestor of maize, other theory establishes that maize was obtained during the domestication process of teosinte. The Mangledorff's tirpartite hypothesis proposes that maize comes from the hybridization in natural conditions of teosinte del Balsas (parviglumis) with an ancestor now disappeared.

    Finally, early on 80's decade, Iltis proposes a theory which establishes that teosinte became into maize in a single macroevolutionary step. Recent genetical studies performed by Doebley seem to discard the Iltis' hypothesis and strength Mangeldroff's theory.

    In this research we wish to expose the experiments performed in the last 5 years that seem to support Ilts' theory of a single evolutionary step from teosinte to maize.

    During the Summer of 1991, seeds of teosinte free of maize intrusion were treated with increasing concentrations of cupric sulfate. In the course of this experiment, we could see an increase of the anthocyanin synthesis, as well as a rise in the number of fused seeds (Pith abscission gene), at 200 ppm of copper we could obtain an Iltis' ear. Subsequent harvesting of this genetic line have allowed us to obtain corncobs with prehistorical characteristics.

Information about the volcanoes
Thus, with this experimental data, it´s proposed that the triangle formed by the volcanoes Pico de Orizaba, La Malinche, and the complex Popo-Izta-Tlaloc gave in a certain moment the enough quantity of heavy metal in the water pouring to the natural reserve (Tehuacan Valley Puebla), not only to convert one time teosinte to maize, instead several times.
Use this sensitive map to obtain information about the volcanoes surrounding Tehuacán Valley

     Follow this link to know deeper the researching performed by LQPN about the topic of the origin and evolution of maize.

Versión en español

Work exposed in the Congreso Internacional de Etnobotánica'97 at Yucatán México.