Which definition describes bacterial transformation?

• A. Uptake of foreign DNA from the environment and incorporation into genome
• B. Transfer of DNA via virus
• C. Inheritance through vertical transmission
• D. Direct transfer of DNA from one bacterium to another

Answer: (A)

Bacterial transformation is the uptake of naked DNA from the environment by competent cells and its incorporation into the genome or maintenance as an extra-chromosomal element. This horizontal gene transfer allows a bacterium to acquire new traits, such as antibiotic resistance, after taking up DNA released from other cells. Natural competence can be improved or induced in the lab to study and exploit this process.

This mechanism is different from other ways bacteria exchange genetic material. Transfer of DNA via virus describes transduction, where bacteriophages carry DNA between cells. Inheritance through vertical transmission refers to genes being passed from parent to offspring during cell division, not the horizontal transfer between unrelated cells. Direct transfer of DNA from one bacterium to another without a viral intermediary describes conjugation, which typically involves a plasmid and a mating bridge between cells.