Recombinant DNA technology creates genetically modified organisms (GMOs) by combining DNA from different sources or inserting foreign DNA into an organism's genome, thereby altering its characteristics.
Here's a breakdown of the process:
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Identifying a Desirable Trait: The process begins by identifying a specific trait in one organism (e.g., insect resistance in a certain plant species) that would be beneficial to another (e.g., a crop plant).
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Isolating the Gene: The gene responsible for the desirable trait is isolated from the source organism's DNA. This often involves using restriction enzymes, which act like molecular scissors, to cut the DNA at specific sequences flanking the gene. Polymerase Chain Reaction (PCR) can also be used to amplify the gene.
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Creating Recombinant DNA: The isolated gene is then inserted into a vector, which is a carrier molecule, often a plasmid (a circular DNA molecule found in bacteria) or a virus. This process involves using restriction enzymes to cut the vector DNA and then using DNA ligase to join the gene and vector DNA together, forming recombinant DNA.
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Introducing the Recombinant DNA into the Host Organism: The recombinant DNA is introduced into the host organism's cells. This can be achieved through various methods, including:
- Agrobacterium-mediated transformation (in plants): The recombinant DNA is inserted into Agrobacterium tumefaciens, a bacterium that naturally infects plants. The bacterium is then used to transfer the recombinant DNA into the plant cells.
- Gene gun (in plants and animals): Tiny gold or tungsten particles are coated with the recombinant DNA and then shot into the host cells.
- Microinjection (in animals): The recombinant DNA is directly injected into the nucleus of the host cell.
- Electroporation: Using electrical pulses to create temporary pores in the cell membrane, allowing the recombinant DNA to enter.
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Integration and Expression: The recombinant DNA integrates into the host organism's genome. The inserted gene is then expressed, meaning the host organism produces the protein encoded by the gene, leading to the desired trait.
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Selection and Propagation: The modified cells are selected and propagated to create a population of GMOs. Selection often involves using a marker gene (e.g., antibiotic resistance) that is introduced along with the desired gene. Only cells that have successfully incorporated the recombinant DNA will survive in the presence of the antibiotic.
In summary, recombinant DNA technology enables the transfer of specific genes from one organism to another, resulting in GMOs with new and desirable traits.
