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GMO transgenes in Mexican maize


Matthew Hufford, a UC Davis graduate student and trainee in the Biological Invasions IGERT, worked with an international team of scientists to study the genetics of Mexican landraces of maize. There has been considerable concern about planting seeds from transgenic (genetically modified) corn in Mexico because of potential spread of genes from transgenic corn into native landraces. Research by other investigators has been equivocal. Hufford and his collaborators confirmed the presence of transgenes from genetically modified (GM) corn in three of 23 locations sampled in 2001. GM corn transgenes were not detected in samples from 2002, but were again found in two of the positive locations resampled in 2004. These results suggest that corn transgenes either persist or have been reintroduced in some localities in Mexico. Further, they presented theoretical results that suggest that the spatial distribution of GM transgenes may be highly aggregated.

This research was published in the journal Molecular Ecology (Pineyro-Nelson et al. 2009)

Address Goals

Transgenic corn is shipped all over the world and has been a source of considerable social, scientific, and political controversy because of the potential for cross-pollination between transgenic corn and landraces, and thus for spread of transgenes into native, locally adapted varieties. Previous publications on this topic have led to opposing conclusions. Hufford and his collaborators showed how sampling methods, analytical procedures, and statistical analyses led to differing conclusions about the presence of maize transgenes. They also made recommendations about the establishment of monitoring protocols to detect the presence of transgenes among landraces of Mexican maize.