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Why have some insect pests developed resistance to Bt toxin?

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DNA extraction and recombinant DNA technology — recombinant DNA The process of DNA extraction is necessary to isolate molecules of DNA from cells or tissues. A series of steps, including the use of protease enzymes to strip proteins from the DNA, are required for isolating pure DNA that is suitable for use in later procedures, such as cloning or sequencing.

Insect pests have developed resistance to Bt toxin primarily as a result of repeated exposure to the protein in genetically modified crops. When pest populations are consistently subjected to the same toxin, individuals with natural genetic variations that allow them to survive the insecticide are more likely to reproduce and pass those traits to the next generation, leading to a resistant population.1

This development is a significant concern because it threatens to render one of the most environmentally benign pest control methods ineffective. To manage this risk, agricultural experts implement strategies such as the planting of "refuges"—areas of non-Bt crops grown near Bt fields—to maintain a local population of insects that remain susceptible to the toxin, thereby slowing the evolution of resistance. Currently, resistance has already been observed in certain moth and cotton pest populations.1