GM Crops
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In 1973, the first recombinant DNA was created and this new development has allowed scientists to move genes around from different organisms (Morris, 2006). Plants were also tested with this new technology and as a result, genetically modified crops were created. These crops had DNA that had been modified to create new traits that may not have been a natural occurrence in these crops. Genetically modifying these plants begins when the scientist identifies a gene from another plant in which there is a desired trait (Shmaefsky, 2006). Through the use of enzymes, they can then remove this gene. This gene is then added to a cloning vector, which is a tiny piece of DNA (Shmaefsky, 2006). The cloning vector with the desired trait can now be duplicated several times by placing it into the cells of yeast or bacteria (Shmaefsky, 2006). Once these vectors have been tested and function normally, they can be inserted into the plant with the undesired traits (Shmaefsky, 2006). After testing the new plant and checking if the altered gene remains for further generations, the scientist may then decide to grow these plants on actual farmland (Shmaefsky, 2006). Some examples of new traits include more nutritious plants, herbicide resistant crops, insect resistant, crops, disease resistant crops and drought resistant crops (Morris, 2006). Fruits could also be prevented from softening or spoiling. Genetically modifying crops could allow the farming of these crops in areas that once were thought of as unusable for farming (Pask, 2007).
Flavr Savr Tomato
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The issue with tomatoes:
In the 1980's, researchers found that the enzyme PG (Polygalacturonase) in tomatoes was responsible for the softening of tomatoes once they had ripened. PG was able to dissolve cell-wall pectin, which is what cause the softening of the tomatoes (Bruening, 2000). Pectin is a molecule located in the middle lamella of all plants and helps in keeping the wall strong and intact, in fact it so useful in holding things in place that it is commonly used as a gelling agent in jellies and jams (Stephens, 2006). Once the ripening process in tomatoes began, PG enzymes break down the pectin in the middle lamella and therefore the middle lamella breaks down, causing cells to split apart. This would mean the tomato is softer as the walls holding the cells together have been broken down.
Creation of Flavr Savr tomatoes:
Researchers in the company Calgene, located in California, were able to produce an antisense version of the gene for PG, which would cancel out the normal versions of PG and therefore reduce the amount of PG created in the plants (Pendick, 1992). Normally, the gene would create RNA, a messenger which carries genetic information from the nucleus to ribosomes, which are located in cells and create proteins (Pendick, 1992). So instead of these RNA messengers telling ribosomes to create PG, the antisense RNA join onto a "normal" RNA and prevent it from reaching the particular proteins which would create PG (Pendick, 1992). This meant the tomatoes would stay firm longer and could remain on the vine for much longer, allowing the full flavour of the tomato to be created (Bruening, 2000). These genetically modified tomatoes were named Flavr Savr tomatoes.
In the 1980's, researchers found that the enzyme PG (Polygalacturonase) in tomatoes was responsible for the softening of tomatoes once they had ripened. PG was able to dissolve cell-wall pectin, which is what cause the softening of the tomatoes (Bruening, 2000). Pectin is a molecule located in the middle lamella of all plants and helps in keeping the wall strong and intact, in fact it so useful in holding things in place that it is commonly used as a gelling agent in jellies and jams (Stephens, 2006). Once the ripening process in tomatoes began, PG enzymes break down the pectin in the middle lamella and therefore the middle lamella breaks down, causing cells to split apart. This would mean the tomato is softer as the walls holding the cells together have been broken down.
Creation of Flavr Savr tomatoes:
Researchers in the company Calgene, located in California, were able to produce an antisense version of the gene for PG, which would cancel out the normal versions of PG and therefore reduce the amount of PG created in the plants (Pendick, 1992). Normally, the gene would create RNA, a messenger which carries genetic information from the nucleus to ribosomes, which are located in cells and create proteins (Pendick, 1992). So instead of these RNA messengers telling ribosomes to create PG, the antisense RNA join onto a "normal" RNA and prevent it from reaching the particular proteins which would create PG (Pendick, 1992). This meant the tomatoes would stay firm longer and could remain on the vine for much longer, allowing the full flavour of the tomato to be created (Bruening, 2000). These genetically modified tomatoes were named Flavr Savr tomatoes.