Horizontal gene transfer

Definition

Horizontal gene transfer is the movement of genetic material between organisms other than by the vertical transmission of DNA from parent to offspring. It plays a significant role in the evolution and adaptation of microbes.

5 Must Know Facts For Your Next Test

1. Horizontal gene transfer can occur through transformation, transduction, or conjugation.
2. It contributes to the spread of antibiotic resistance among bacterial populations.
3. Transformation involves the uptake of naked DNA from the environment by a bacterium.
4. Transduction is mediated by bacteriophages that transfer genetic material between bacteria.
5. Conjugation requires direct cell-to-cell contact and involves the transfer of plasmids.

Review Questions

• What are the three main mechanisms of horizontal gene transfer?
• How does horizontal gene transfer contribute to antibiotic resistance?
• Describe how conjugation differs from transformation and transduction.

Related terms

Transformation:

A process where bacteria take up free-floating genetic material from their environment.

Transduction:

The process by which bacterial DNA is transferred from one bacterium to another by a virus.

Conjugation:

A form of horizontal gene transfer where two bacteria connect via a pilus to exchange genetic material.