BIO120H1 Lecture Notes - Lecture 13: Herbicide, Evolutionary Medicine, Glyphosate
23 Oct 2018
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Agricultural relevance: pesticide and herbicide resistance. Evolutionary medicine: evolution of resistance to antibiotics, evolution-proof vaccination. Global change and evolution: adapt or go extinct. We have chemicals we use to combat pests and pathogens, including weeds, insects, bacteria, tumors. We are creating strong selective pressure for resistance. In us alone, translates to 26 billion dollars of losses. Weeds cause approx 34% loss of crop yields annually. Weedy plants have repeatedly evolved resistance to herbicides. The rise of superweeds weed species often become resistant to herbicides; glyphosate resistance, once deemed unlikely, rose after genetically engineered crops were introduced in the mid-1990"s. Where does resistance come from: pre-existing genetic variation in the population, new mutations: in very large populations new, simple mutations may be introduced at a high rate, epidemic spread" of resistance from one region to the next. Out crossing weeds have more pre-existing resistance variation than selfing weeds.
