Familiar with Roundup? It's a highly toxic chemical that kills nearly anything it touches. Crops were "bioengineered" to be tolerant to roundup. Farmland was then saturated with Roundup, killing only the undesirable plants (weeds).

"Testing" the bioengineered crops would have revealed no problematic effects to the plant. But it turns out human consumption of Roundup is VERY harmful.... nature would have never produced a plant immune to Roundup. Gene editing did. Unfortunately the second/third order effects became apparent only after the practice was already mainstream.... this is a large contributor to America's food supply being toxic