Scientists thought they understood maize ’s origins. They were missing something big

Maize is one of the world’s most important crops, but its origins have long bedeviled scientists. It took more than a century for scientists to settle on the idea that it was domesticated about 9000 years ago in the lowlands of Mexico from a wild grass: a subspecies of teosinte called parviglumis . But now, a team of geneticists has complicated that history, reporting today in Science that maize as we know it has a second wild ancestor . Between 15% and 25% of the genes in all existing maize varieties come not from parviglumis , but from a highland subspecies of teosinte called mexicana , which hybridized with maize some 4000 years after people first domesticated the plant. Maize is “such a well-studied and prominent plant” that it’s surprising to learn it had a long-lost relative, says Logan Kistler, an anthropologist who studies plant domestication at the Smithsonian Institution’s National Museum of Natural History. “There’s still something this basic to learn about maize—that’s wild.” But why the new hybrid spread so far and wide is still unclear. Jeffrey Ross-Ibarra, an evolutionary biologist at the University of California, Davis, started to study the relationship of the mexicana teosinte subspecies to maize in order to understand how the lowland domesticate adapted to the chilly highlands of central Mexico. But, “We kept finding evidence of this second teosinte in oth...
Source: ScienceNOW - Category: Science Source Type: news