Conjugation transformation, and transduction are all ways that bacteria

There are numerous bacteria found on planet earth. They divide quickly by binary fission producing identical daughter cells. Thus, the genetic information is transferred from the mother to the offspring and is known as vertical transmission.

The mutations are transferred from one bacteria to another through horizontal transmission. There are three different types of horizontal transmission for the transfer of genetic information.

• Conjugation
• Transduction
• Transformation

Bacterial Conjugation

Conjugation is the method of transfer of genetic material from one bacteria to another placed in contact. This method was proposed by Lederberg and Tatum. They discovered that the F-factor can move between E.coli cells and proposed the concept of conjugation.

There are various conjugal plasmids carried by various bacterial species. Conjugation is carried out in several steps:

• Mating pair formation
• Conjugal DNA synthesis
• DNA transfer
• Maturation

Also Read: R-Factor

Mechanism of Bacterial Conjugation

Bacterial conjugation involves the following steps:

Pilus Formation

The donor cells (F+ cells) form a sex pilus and begin contact with an F- recipient cell.

Physical Contact between Donor and Recipient Cell

The pilus forms a conjugation tube and enables direct contact between the donor and the recipient cells.

Transfer of F-Plasmid

The F-factor opens at the origin of replication. One strand is cut at the origin of replication, and the 5’ end enters the recipient cell.

Synthesis of Complementary Strand

The donor and the recipient strand both contain a single strand of the F-plasmid. Thus, a complementary strand is synthesized in both the recipient and the donor. The recipient cell now contains a copy of F plasmid and becomes a donor cell.

Also Read: Difference between Virus and Bacteria

Bacterial Transduction

Transduction is the process of transfer of genes from the recipient to the donor through bacteriophage.

Transduction is of two types:

• Generalized Transduction
• Specialized Transduction

Generalized Transduction

In this type, the bacteriophage first infects the donor cells and begins the lytic cycle. The virus then develops its components using the host cell machinery. The host cell DNA is hydrolyzed into small fragments by the viral enzymes.

Small pieces of bacteria DNA is now integrated into viral genome. When the virus infects another bacteria the DNA is transferred into it.

Specialized Transduction

In this, only a few restricted bacteria are transferred from donor to recipient bacteria. This is carried out by temperate bacteriophage which undergoes the lysogenic cycle.

The virus enters the bacteria and integrates its genome within the host cell DNA. It remains dormant and passes on from generation to generation. When the lysogenic cell is exposed to some external stimulus, the lytic cycle begins.

The viral genome is induced in the host cell genome. Due to this, the phage genome sometimes carries the bacterial genome with it and integrates it into the genome of the recipient cell. Here, only the restricted genome has the possibility of entering the recipient cells.

Bacterial Transformation

Transformation is the process of uptake of genetic material by bacteria from its surroundings. It is utilized in genetic engineering to introduce a foreign gene into the bacterium.

People commonly understand how major plants and animals exchange genetic information. But the ways in which microbes like bacteria do something similar are often overlooked.

Bacteria rely on several different mechanisms for the exchange of genetic materials. In one case, a bacterial cell may transfer genetic information directly into another bacterial cell through a process called conjugation.

In conjugation, one bacterium grows a duct, called a pilus, which attaches to the other bacterium. A genetic element known as a plasmid is then passed through the pilus from the donor cell to the recipient.

In another case, viruses play a role in genetic exchange between bacteria. Bacterial viruses, or bacteriophages (sometimes just called “phages”) ordinarily attach themselves to bacterial cells and then inject their genetic material into the cells. Such viruses hijack bacteria, using bacterial cell components to generate new phage particles.

In some cases, a phage’s reproduction cycle kills the host bacterium. In other cases, the bacterium survives. This occurs when the virus’s DNA becomes incorporated into the bacterium’s DNA. At this stage, the virus depends on the host bacterium for the replication of new phage particles.

When the new phages emerge from the host, some may carry pieces of bacterial DNA. If the new phages attach to other bacteria and the DNA becomes incorporated into bacterial DNA, new genetic types of bacteria may be produced. This process, in which bacteriophages assist in the genetic recombination of bacteria, is known as transduction.

What do transduction transformation and conjugation have in common?

What are the 3 methods of genetic transfer in bacteria?

In what ways will the processes of transformation transduction and conjugation differ?

What are the 3 methods of genetic recombination?