Bacterial gene transfer differs from eukaryotes. Bacteria can transfer their genes both vertically and horizontally.

1. Vertical Gene Transfer

Genetic material is passed on from parent to the offspring vertically.

---

2. Horizontal (Lateral) Gene Transfer

Horizontal gene transfer (HGT or LGT) can be defined as the acquisition of a DNA fragment from elsewhere.

Physical transfer of DNA from one cell to another:

• Transformation: Naked bacterial DNA fragment is taken from the environment by bacteria.
• Transduction: Bacterial DNA fragment is transferred from one cell to another via viruses (phage).
• Conjugation: Bacterial DNA fragment is transferred by cell-to-cell contact between bacteria. It may entail the transfer of a plasmid or transposon.