Marker Free GM Soybean Produced by Gene Excision

Marker genes, usually for antibiotic resistance, have always been the focus of criticisms in genetic improvement of crops. Various selectable marker genes are used in plant transformation systems to select transgenic events, but often the marker gene is no longer needed after the transgenic plants are regenerated. A group of researchers from DuPont recently produced marker-gene-free glyphosate-tolerant transgenic soybean lines through a self –activating gene excision system.

Unlike other approaches to produce marker-free plants, the gene excision system employed by the researchers delivers precise outcomes and does not require additional manipulations of the transformation and regeneration process. The glyphosate tolerance and marker genes were introduced together with a gene coding for the enzyme, Cre recombinase, which will instantly remove itself and the marker gene upon induction. This self-activating gene excision strategy is currently being applied to numerous plants like maize, cotton, peanut, and many coniferous trees.

The full paper is available at http://www.springerlink.com/content/m5725xk427115102/fulltext.pdf Non subscribers can read the abstract at http://www.springerlink.com/content/m5725xk427115102/?p=baabe18c455f40d38cfe38220db07408&pi=0