Evaluating the risk of transgene spread from Brassica napus to related species

There is a need to evaluate the likelihood of the sexual spread of transgen es from genetically modified crops to wild species. We attempt to estimate this by crossing a transgenic (hemizygous) line of oilseed rape to weed spe cies with which it has varying degrees of sexual compatibility. The offspri ng were selfed and backcrossed in order to examine the inheritance of the t ransgene in subsequent generations. We found that while the transgene was i nherited in a normal Mendelian fashion for the first generation, most of th e offspring were infertile. However, analysis of those that are fertile cou ld be very informative in estimating the risk of transgene spread in differ ent genetic backgrounds.