Screening
Genetically modified plants (gm plants) contain foreign genes that provide the plants with new properties like herbicide tolerance or insect resistance. The function of genes depends on certain regulatory DNA sequences, so-called promoters and terminators.
All gm plants approved in the EU and most of the plants cultivated worldwide contain such regulatory sequences. The most common ones are the 35S promoter from the cauliflower mosaic virus (CaMV) and the nos terminator, i.e. the 3`untranslated region of the nopaline synthase gene from agobacterium tumefaciens.
Since many different gm plants contain the identical regulatory sequences a positive screening result strongly indicates the presence of some genetic modification but does not allow the unambiguous identification of a specific gm plant.