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How does a transgene become part of an organism's genome?
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recombinant DNA
The process of DNA extraction is necessary to isolate molecules of DNA from cells or tissues. A series of steps, including the use of protease enzymes to strip proteins from the DNA, are required for isolating pure DNA that is suitable for use in later procedures, such as cloning or sequencing.
In the context of genetic engineering, a transgene can become part of an organism's genome through several sophisticated molecular techniques. It is important to clarify that while many recombinant DNA applications involve inserting foreign genes into plasmids—which exist independently of the main chromosome—true integration into the genome requires specific mechanisms.1
Methods for incorporating a transgene into an organism's genome include:
- Homologous Recombination: This process uses the cell's natural DNA repair machinery. By introducing foreign DNA flanked by sequences identical to a target site, the cell recognizes these regions as homologues and swaps the target sequence with the transgene. This is a primary method for gene targeting and creating "knockout" models.2
- Viral Vectors: Engineered viruses are frequently used as delivery tools. After being modified to remove harmful viral genes, these vectors can transport a transgene into a target cell, where they may integrate the genetic material directly into the host cell's DNA.3
- Gene Editing: Technologies such as CRISPR-Cas9 allow for precise modifications. Researchers can target specific nucleotide sequences to introduce, remove, or replace segments of genetic material, effectively inserting a transgene into a desired location within the genome.1
When a transgene is inserted, it may integrate into a chromosomal site different from the intended location, which carries the risk of disrupting other functional genes.1