Horizontal gene transfer (HGT)

Definition

Horizontal gene transfer (HGT) is the movement of genetic material between organisms other than through vertical transmission (from parent to offspring). It plays a significant role in the evolution of many species, including bacteria and archaea.

5 Must Know Facts For Your Next Test

1. HGT can occur via transformation, transduction, or conjugation.
2. It contributes to the spread of antibiotic resistance among bacterial populations.
3. HGT challenges the traditional tree-like model of evolution by introducing a network-like structure.
4. It has been observed in both prokaryotes and eukaryotes, though it is more common in prokaryotes.
5. Mechanisms of HGT include plasmids, bacteriophages, and mobile genetic elements.

Review Questions

• What are the three primary mechanisms through which horizontal gene transfer occurs?
• How does horizontal gene transfer impact the traditional phylogenetic tree model?
• Why is horizontal gene transfer particularly significant in the context of antibiotic resistance?

Related terms

Transformation: The process by which a cell takes up foreign DNA from its surroundings.

Transduction:

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

Conjugation:

A mechanism of horizontal gene transfer involving direct cell-to-cell contact for DNA transfer.