Bacteria and Archaea Genetic Diversity
How do Bacteria and Archaea increase the genetic pool?
Final answer: Bacteria and Archaea increase genetic diversity via horizontal gene transfer, using processes like transformation (DNA uptake from the environment), transduction (gene transfer by viruses), and conjugation (plasmid and DNA transfer via a pilus).
Bacteria and Archaea increase genetic diversity through a process called horizontal gene transfer (HGT). This mechanism allows for the exchange of genetic material between individual bacteria and archaea, leading to increased genetic variation within their populations.
Horizontal gene transfer involves three main processes:
1. Transformation
In transformation, bacteria and archaea pick up free DNA fragments from their environment. These DNA fragments can come from other prokaryotes, whether they are alive or dead. By incorporating this external DNA into their own genome, bacteria and archaea can acquire new genetic traits. This process can lead to significant changes in their characteristics, such as increased virulence in previously nonpathogenic bacteria.
2. Transduction
Transduction is the movement of genetic material from one bacterium to another via bacteriophages, which are viruses that infect bacteria. This process allows for the transfer of genetic traits between individuals, further contributing to genetic diversity within bacterial and archaeal populations.
3. Conjugation
Conjugation involves the direct transfer of DNA, typically in the form of plasmids, between two bacterial or archaeal cells. This transfer is facilitated by a pilus that connects the two cells. Sometimes, parts of the chromosome itself can be transferred during conjugation, leading to the exchange of genetic material and increasing genetic diversity.
These processes of horizontal gene transfer enable bacteria and archaea to introduce genetic variation into their populations, despite reproducing asexually through methods like binary fission, budding, and fragmentation. By acquiring new genetic traits, bacteria and archaea can adapt to changing environmental conditions and evolve over time.