Seeds are genetically modified by identifying genes with desirable traits, copying those genes, and then inserting them into the seed's DNA.
Here's a more detailed breakdown of the process:
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Identifying a Desirable Trait: Scientists first identify a specific characteristic they want to introduce into the plant. This could be insect resistance, herbicide tolerance, improved nutritional content, or increased yield.
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Finding the Corresponding Gene: Once the desired trait is identified, researchers locate the gene responsible for that trait. This gene might come from a different strain of the same plant species, a related plant species, or even from a completely different organism, like a bacterium.
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Copying the Gene: After locating the gene, scientists make copies of it. This is often done using techniques like polymerase chain reaction (PCR), which amplifies the gene to produce many identical copies.
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Inserting the Gene into the Plant's DNA: There are several methods for introducing the desired gene into the plant cells. Two common methods include:
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Agrobacterium tumefaciens mediated transformation: Agrobacterium tumefaciens is a bacterium that naturally infects plants and transfers DNA into their cells. Scientists can modify Agrobacterium to carry the desired gene and then infect plant cells with it. The bacterium then transfers the gene into the plant's DNA.
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Gene Gun (Biolistics): This method involves coating tiny gold or tungsten particles with the desired gene and then shooting these particles into plant cells using a gene gun. Some of these particles will penetrate the cell's nucleus and the DNA containing the new gene will integrate into the plant's genome.
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Selection and Regeneration: After the gene is inserted, scientists select the plant cells that have successfully incorporated the new gene. These cells are then grown into whole plants using tissue culture techniques.
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Testing and Evaluation: The genetically modified plants are rigorously tested in greenhouses and field trials to ensure they express the desired trait effectively and do not have any unintended negative effects on the environment or human health. Bt corn, mentioned in the reference question, is an example of a genetically modified crop that is resistant to certain insects.
In essence, genetic modification of seeds involves a precise and targeted alteration of the plant's DNA to introduce specific, beneficial characteristics.
