Biodiversity (Communications arising): suspect evidence of transgenic contamination.

Quist and Chapela claim that transgenic DNA constructs have been introgressed into a traditional maize variety in Mexico, and furthermore suggest that these constructs have been reassorted and introduced into different genomic backgrounds. However, we show here that their evidence for such introgression is based on the artefactual results of a flawed assay; in addition, the authors misinterpret a key reference to explain their results, concluding that reassortment of integrated transgenic DNA occurs during transformation or recombination.