The following is a paper that I wrote for my population genetics class. 

Corn is a large part of the diet of North Americans. Furthermore, 15 percent of the land coverage of genetically modified crops contain Bt proteins (Hoftmann 2011). Bt corn was created because there is a high demand for corn that is damage free. Corn pests include wireworms (Elateridae sp.), cutworms (Noctuidae sp.), European corn borer (Ostrinia nubilalis), corn earworm (Helicoverpa zea), and white grubs (Phyllophaga sp.). In the past, the soil had to be treated before planting in order for the plants to be unaffected. Affected plants had stunted growth which led to a reduction in their yield. Not all pre-planting treats were effective either. (University of Kentucky) In the past, in order to deal with these pests crop rotation was also used. The areas most affected by these pests were Illinois, Indiana, Michigan, Ohio, and Iowa.

 

Bt corn first appeared in 1996 in Zurich Switzerland. Monsanto had the corn in development since 1992. The genes cry1Ab, bar, and bla were put into the corn. The cry1Ab gene comes from Bacilus thuringiensis, bar from Streptomyces hygroscopicus, and bla from Esherichia coli. Cry1Ab makes the crop resistant to lepidopteran species (butterflies and moths) by damaging midgut lining. It breaks down the gut wall which allows bacteria to flood into the body cavity. Bar makes crops resistant to herbicides by eliminating the activity of glufosinate in cells. It does this by acetylation. Bla detoxifies beta lactam antibiotics. This paper will focus on the bar insertion that causes resentence to pests, the Bt gene. Current the crop is used for food in 13 countries, feed in 10, and cultivation in 4 (International Service for the acqaution of agro-biotech applications.) Currently, Monsanto is working on increasing the resistance with corn rootworms (Diabrotica virgifera) and pink bollworms (Pectinophora gossypiella) (Monsanto 2015).

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