Pooling Our Resources: Leading the Fight to Understand and Conserve the Zea Gene Pool.

Pooling our resources: leading the fight to understand and conserve the Zea gene pool Marilyn Warburton The origin of maize (Zea mays L. ssp. mays) has been one of the more discordantly argued subjects in biology, with hypotheses and arguments from many well known scientists. Cumulative historical, archeological, and genetic evidence finally allowed one theory, the single domestication event from Balsas teosinte (Zea mays ssp. parviglumis), to win the debate. However, this domination of the debate caused further discussions regarding genetic contributions into domesticated maize from other sources to be muffled until some champions such as Garrison Wilkes, and eventually the authors of the single domestication theory themselves, began to suggest that other taxa contributed as well. New genetic studies show that diversity in maize has increased via gene flow from various teosinte taxa, and the directions, rate and final impact of this flow on maize evolution is now being measured. New techniques that characterize large numbers of individuals per population or use very high marker densities show that gene flow into maize from other teosintes, and between different teosintes, has occurred frequently. Evidence for contributions from the Balsas teosintes and from Chalco teosintes (Z. mays ssp. mexicana) into the maize gene pool are presented here, as well as from Chalco into ssp. mexicana race “Durango” and Z. mays ssp. huehuetenengensis. These are almost certainly the result of post-domestication (and ongoing) exchanges. This information must give more impetus to in situ conservation of the primary gene pool teosinte species, as well as secondary gene pool Tripsacums, and use of these materials to continue to direct maize evolution, especially in response to new biotic and abiotic stresses. The conservation and use of maize and its wild relatives have been studied and advocated by maize genetics pillars, including Garrison Wilkes, Suketoshi Taba, Major Goodman, and Jesus Sanchez. We ignore this call at great risk to future maize improvement.