In this video, I look at the three methods bacteria use to share genetic information: Conjugation, Transduction, and Transformation.
Bacteria typically increase their numbers through a process akin to cloning; that is, they make exact copies of themselves. While this method is efficient, it presents a significant evolutionary limitation: genetic diversity can only arise through random mutations. In the absence of a mechanism for exchanging genes, bacteria would be stuck in a genetic standstill, unable to benefit from the rapid spread of advantageous traits. Bacteria solve this problem by horizontal gene transfer (HGT), which is also called lateral gene transfer (LGT).
To help the spread of advantageous genes in a bacteria population, the bacteria use three methods to exchange DNA:
- Conjugation: This process involves direct physical contact between two bacteria through a structure called a sex pilus. A donor bacterium with an F plasmid (F+) forms a bridge to a recipient bacterium (F-), transferring a copy of its DNA. This method not only promotes genetic diversity but also allows for the rapid spread of advantageous traits such as antibiotic resistance.
- Transduction: In this method, bacteriophages (viruses that infect bacteria) play a crucial role. When a virus infects a bacterium, it sometimes incorporates fragments of the host's DNA into its own genetic material. As the virus infects new bacterial cells, it transfers these DNA fragments, facilitating genetic exchange.
- Transformation: This process occurs when bacteria take up free-floating DNA from their environment, often released by dead bacterial cells. The acquired DNA is then incorporated into the recipient's genome, providing new genetic traits that can be beneficial for survival and adaptation.
In the video, I examine the three methods.
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