what-is-a-gmo.ppt

Editor's Notes

• #3: Scientists originally never used the term genetically modified organisms or GMOs to describe genetic engineering. This term seems to have come from the popular media. The term has become so common that even scientists often use the term now. For many the terms genetically modified organisms are synonymous with genetically engineered organisms. Most scientists would say that almost all the food we eat has been "genetically modified" by man and that genetic modification includes not only conventional breeding, but simple selections man has made over millennia.  Picture 1 teosinte to modern corn – 7000 years, Picture 2 on right - wild carrot vs modern carrots, orange carrots were developed in 1700’s, Picture 3 The exact date of domestication of tomato is unknown: by 500 BC, it was already being cultivated in southern Mexico and probably other areas.
• #4: Picture 1 center picture is wild cabbage (brassica oleracea) man selected the other crops pictured from this plant. Top row pictures left to right – cabbage, kale, broccoli Bottom row pictures left to right – brussel sprouts, kohlrabi and cauliflower
• #5: You may prefer this slide to the previous one. More info on what was selected for.
• #8: Chart compares methods of producing new crop varieties. Number of genes affected is a measure of the precision. Since only one or a few genes are moved/deleted/alltered in genetic engineering (last 2 columns, transgenics and cisgenics) you know what protein will be produced and can test for toxicity and allergenicity. The little r before DNA is for recombinant.
• #12: Both apples (Arctic apples) and potatoes (first generation Innate potatoes) have been genetically engineered so that they do not brown when cut open and reduce losses due to bruising. Both are examples of RNAi, which uses genes from the same species, for gene silencing. The potato also reduces acrylamide in potatoes. Acrylamide has been linked to some cancers. Both products could benefit consumers by reducing food waste. The small company that produced Arctic apples hopes the ability to serve sliced apples that do not brown will increase apple comsumption by children. The second generation of Innate potatoes entered the USDA process on the heels of the recent deregulation of its first generation.  The potatoes will also undergo FDA review and must be registered by the US EPA.  The second generation of Innate contains the same traits as the first generation (low black spot bruise and low acrylamide), plus two additional traits consisting of resistance to late blight disease (regulated by the US EPA) and lowered reducing sugars. Late blight disease is what caused the Irish potato famine and is still a problem that often requires multiple pesticide applications)
• #13: Traditionally, rennet is obtained from the fourth stomach lining of an unweaned calf. Calves have a higher amount of rennet in their stomachs compared to adults as they use it to digest milk, their main source of food. The rennet extracted from the stomach linings is usually a mixture of chymosin, pepsin (another enzyme) and other proteins. Beginning in the 1960s, the price of rennet, a byproduct of the veal industry, rose and became less stable as the animal rights movement grew. Demand for cheese also soared, and cheese-makers began looking for alternative sources of rennet from plants and microbes. Some plants and microbes naturally produce enzymes that have coagulating properties like rennet. However, rennet from these sources tend to produce other side reactions in cheese production, leading to undesirable results in taste. So how did biotechnology come to play a role? In the late 1980s, scientists figured out how to transfer a single gene from bovine cells that codes for chymosin into microbes, giving microbes the ability to produce chymosin. These genetically modified microbes are allowed to multiply and cultivated in a fermentation process while they produce and release chymosin into the culture liquid. The chymosin can then be separated and purified. Chymosin produced using this method is termed fermentation-produced chymosin, or FPC.