Efforts to design genetically modified (GM) crops have focused on minimizing the amount of foreign DNA present in the genome. One reason for this development is to address consumer concerns about unforeseeable effects of either the transgenes or the technology used to introduce them into plant genomes. The latter risk has not been completely assessed, but the former can be dealt with both by minimizing the amount of the foreign DNA inserted and by taking precautionary steps in the selection and adaptation of the transgene itself. In fact, first‐generation GM crops contain many unnecessary DNA sequences, such as antibiotic‐resistance genes and T‐DNA border sequences. These efforts, however, are not only in response to consumer concerns; they will also be helpful to GM engineers. To make maize tolerant to high sodium concentrations, for example, it only requires the introduction of a salt‐tolerance gene. Other DNA sequences, such as antibiotic‐resistance genes, are only needed to select transgenic cells. Afterwards, they become unnecessary at best and detrimental at worst, as they …