Two papers discuss risks associated with the use of the DNA sequence 35S (originating from the cauliflower mosaic caulimovirus) in transgenic plants. The 1st paper (by J. J. Perrier) presents the viewpoints of opposing scientists. The 2nd paper (by J. B. Morel and M. Tepfer) discusses the possibility of 35S to activate viral genomes and genes in plants (due to the existence of a 'hot point' for recombination).