Jan 7, 2011

Glossary

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Bacterial conjugation

The direct transfer of genetic material from a donor cell to a recipient cell

Bacteria use conjugation to exchange DNA. The exchange takes place in one direction: one cell acts as the DNA donor, while the other is the recipient. The donor cell forms a thread-like growth, the F pilus (the F stands for fertility) which attaches to the partner cell. The DNA exchange takes place via this temporary cell ‘bridge’.

The ability to form F pili and transfer DNA during conjugation depends on the presence of a special F plasmid. This plasmid occurs in the bacterial cell either as a free DNA ring (F+ cells) or integrated within the main chromosome. This results in cells known as Hfr cells (high frequency of recombination) because they exchange genetic material with other bacteria very frequently.