MODEL RELEASED. Genetically engineered tomato plants. Geneticist Dr Virginia Ursin examines cultures of Flavr Savr tomato plants, the first genetically engineered whole food. Each dish contains seedlings cultured from a single cell, grown on agarose medium. Flavr Savr tomatoes have a gene which allows the fruit to ripen on the vine without softening; so they are tastier, don't need ripening with ethylene gas, and are not damaged during shipping. Tomato softening occurs due to the enzyme polygalacturonase. Flavr Savr tomatoes contain an anti-sense" gene which blocks the enzyme. This tomato entered American supermarkets in May 1994. Research at Calgene, California, USA."