What is the name of the process by which bacteria transfer DNA via a pilus?

The process by which bacteria transfer DNA via a pilus is called conjugation. It is a form of horizontal gene transfer, meaning genetic material moves between existing cells rather than passing from parent to offspring during reproduction.

In the classic Escherichia coli example, a donor cell carries the F plasmid, which contains genes for the conjugation machinery. The donor produces an F pilus that attaches to a recipient cell and draws the cells together. A transfer system then nicks one strand of the plasmid and moves that DNA strand into the recipient; both cells synthesize complementary strands afterward.

Conjugation commonly spreads plasmids carrying antibiotic-resistance genes, toxin genes, or pathways for using unusual nutrients. The transferred DNA may remain as a plasmid or, in some cases, recombine with the recipient’s chromosome. Conjugation is sometimes informally compared with bacterial mating, but it does not create offspring or involve gametes.

Transformation is different because cells take up free DNA from their surroundings. Transduction uses a bacteriophage to carry DNA between bacteria. Binary fission, meanwhile, is bacterial cell division, not DNA transfer between cells.