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How can weeds become resistant to herbicides used with genetically modified crops?
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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.
Weeds develop resistance to herbicides used with genetically modified (GMO) crops primarily through repeated exposure to the same chemicals, which selects for individuals that can survive the treatment.12
When fields are sprayed liberally with herbicides like glyphosate, susceptible plants are eliminated, leaving behind those that have evolved mechanisms to withstand the chemical. These mechanisms include:12
- Genetic Mutation: Some weeds undergo mutations that lead to the overexpression of the target enzyme (EPSP synthase), prevent the herbicide from interacting with the enzyme, or decrease the plant's uptake and retention of the herbicide.2
- Gene Flow: Resistance can also spread to wild plants through the transfer of pollen or seeds from crops that have been genetically engineered for herbicide resistance.2
This phenomenon has led to the emergence of "super-weeds" that are no longer controlled by standard applications. Relying on these chemicals creates a cycle where farmers may increase herbicide use to combat resistant populations, which can negatively impact biodiversity, soil health, and local ecosystems.1